UIL (UIL) 10-Q 7 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	2-May-14
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'UIL HOLDINGS CORP	'
Entity Central Index Key	'0001082510	'
Current Fiscal Year End Date	'--12-31	'
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	56,532,748
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'

CONSOLIDATED_STATEMENT_OF_INCO

CONSOLIDATED STATEMENT OF INCOME (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CONSOLIDATED STATEMENT OF INCOME (Unaudited) [Abstract]	'	'
Operating Revenues	$571,162	$548,039
Operation	'	'
Purchased power	53,130	38,489
Natural gas purchased	214,925	219,267
Operation and maintenance	92,877	89,259
Transmission wholesale	20,911	18,818
Depreciation and amortization (Note F)	40,318	50,107
Taxes - other than income taxes (Note F)	39,536	35,866
Acquisition-related expenses (Note A)	5,051	0
Total Operating Expenses	466,748	451,806
Operating Income	104,414	96,233
Other Income and (Deductions), net	'	'
Acquisition-related bridge facility fees (Note A)	-6,413	0
Other income and (deductions) (Note F)	3,862	5,361
Total Other Income and (Deductions), net	-2,551	5,361
Interest Charges, net	'	'
Interest on long-term debt	22,452	21,686
Other interest, net (Note F)	175	1,025
Interest charges, gross	22,627	22,711
Amortization of debt expense and redemption premiums	607	601
Total Interest Charges, net	23,234	23,312
Income from Equity Investments	3,386	3,812
Income Before Income Taxes	82,015	82,094
Income Taxes (Note E)	26,550	30,287
Net Income	55,465	51,807
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	13	16
Net Income attributable to UIL Holdings	$55,452	$51,791
Average Number of Common Shares Outstanding - Basic (in shares)	56,779	50,888
Average Number of Common Shares Outstanding - Diluted (in shares)	57,043	51,157
Earnings Per Share of Common Stock - Basic (Note A): (in dollars per share)	$0.98	$1.02
Earnings Per Share of Common Stock - Diluted (Note A): (in dollars per share)	$0.97	$1.01
Cash Dividends Declared per share of Common Stock (in dollars per share)	$0.43	$0.43

CONSOLIDATED_STATEMENT_OF_COMP

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Unaudited) [Abstract]	'	'
Net Income	$55,465	$51,807
Other Comprehensive Income (Loss), net of deferred income taxes [Abstract]	'	'
Changes in unrealized gains (losses) related to pension and other post-retirement benefit plans	61	253
Other	12	-2
Total Other Comprehensive Income (Loss), net of deferred income taxes	73	251
Comprehensive Income	55,538	52,058
Less:	'	'
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	13	16
Comprehensive Income Attributable to UIL Holdings	$55,525	$52,042

CONSOLIDATED_BALANCE_SHEET_Una

CONSOLIDATED BALANCE SHEET (Unaudited) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets	'		'
Unrestricted cash and temporary cash investments	$137,372		$69,153
Restricted cash	2,179		2,046
Accounts receivable less allowance of $14,601 and 12,021, respectively	303,070		245,252
Unbilled revenues	85,474		93,050
Current regulatory assets (Note A)	326,262		332,391
Natural gas in storage, at average cost	32,831		79,917
Deferred income taxes	0		21,742
Refundable taxes	10,550		8,244
Current portion of derivative assets (Note A)	9,073		9,098
Prepayments	21,271		14,989
Other	10,909		12,122
Total Current Assets	938,991		888,004
Other investments	'		'
Equity investment in GenConn (Note A)	116,222		118,241
Other	26,120		26,348
Total Other investments	142,342		144,589
Net Property, Plant and Equipment (Note A)	3,084,168		3,068,680
Regulatory Assets (Note A)	637,784		703,739
Deferred Charges and Other Assets	'		'
Unamortized debt issuance expenses	14,852		15,518
Derivative assets (Note A)	30,868		44,349
Goodwill	266,205		266,205
Other	15,034		13,136
Total Deferred Charges and Other Assets	326,959		339,208
Total Assets	5,130,244	[1]	5,144,220	[1]
Current Liabilities	'		'
Current portion of long-term debt	11,769		11,834
Accounts payable	151,919		164,416
Dividends payable	24,392		24,392
Accrued liabilities	67,597		78,125
Current regulatory liabilities (Note A)	266,892		261,729
Taxes accrued	29,074		23,490
Deferred income taxes	9,434		0
Interest accrued	25,877		21,933
Current portion of derivative liabilities (Note A)	28,519		26,904
Total Current Liabilities	615,473		612,823
Deferred Income Taxes	560,585		540,542
Regulatory Liabilities (Note A)	465,755		445,092
Other Noncurrent Liabilities	'		'
Pension accrued	166,941		170,853
Other post-retirement benefits accrued	85,846		78,539
Derivative liabilities (Note A)	81,374		169,327
Other	46,166		49,047
Total Other Noncurrent Liabilities	380,327		467,766
Commitments and Contingencies (Note J)	'		'
Capitalization (Note B)	'		'
Long-term debt, net of unamortized discount and premium	1,722,622		1,723,842
Preferred Stock of Subsidiary	'		'
Preferred stock, not subject to mandatory redemption	340		340
Common Stock Equity	'		'
Common stock	1,148,782		1,145,950
Paid-in capital	19,658		22,272
Retained earnings	216,102		185,058
Accumulated other comprehensive income (loss)	600		535
Net Common Stock Equity	1,385,142		1,353,815
Total Capitalization	3,108,104		3,077,997
Total Liabilities and Capitalization	$5,130,244		$5,144,220
[1]	Includes $266.2 million of goodwill in the Gas Distribution segment as of March 31, 2014 and December 31, 2013.

CONSOLIDATED_BALANCE_SHEET_Una1

CONSOLIDATED BALANCE SHEET (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets	'	'
Allowance for doubtful accounts receivable	$14,601	$12,021

CONSOLIDATED_STATEMENT_OF_CASH

CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Cash Flows From Operating Activities	'		'
Net income	$55,465		$51,807
Adjustments to reconcile net income to net cash provided by operating activities:	'		'
Depreciation and amortization	40,925		50,708
Deferred income taxes	22,854		-12,500
Allowance for funds used during construction (AFUDC) - equity	-2,550		-2,537
Stock-based compensation expense (Note A)	2,471		2,263
Pension expense	7,835		12,041
Undistributed (earnings) losses in equity investments	-3,388		-3,812
Regulatory activity, net	35,691		73,769
Other non-cash items, net	2,875		-13,084
Changes in:	'		'
Accounts receivable, net	-60,398		-53,701
Unbilled revenues	7,576		13,868
Natural gas in storage	47,086		51,108
Prepayments	-6,282		-8,709
Cash distributions from GenConn	3,271		0
Accounts payable	9,478		-20,850
Interest accrued	3,944		2,308
Taxes accrued/refundable, net	3,278		46,097
Accrued liabilities	-12,768		-18,966
Accrued pension	-10,413		-34,167
Accrued other post-employment benefits	5,973		-2,745
Other assets	418		-1,086
Other liabilities	3,047		341
Total Adjustments	100,923		80,346
Net Cash provided by Operating Activities	156,388		132,153
Cash Flows from Investing Activities	'		'
Plant expenditures including AFUDC debt	-64,692	[1]	-74,637	[1]
Cash distributions from GenConn	2,134		0
Changes in restricted cash	-133		967
Deposits in New England East West Solution (NEEWS) (Note C)	-1,044		0
Other	0		39
Net Cash provided by (used in) Investing Activities	-63,735		-73,631
Cash Flows from Financing Activities	'		'
Line of credit borrowings (repayments), net	0		-34,000
Payment of common stock dividend	-24,421		-21,887
Other	-13		355
Net Cash provided by (used in) Financing Activities	-24,434		-55,532
Unrestricted Cash and Temporary Cash Investments:	'		'
Net change for the period	68,219		2,990
Balance at beginning of period	69,153		17,857
Balance at end of period	137,372		20,847
Non-cash investing activity:	'		'
Plant expenditures included in ending accounts payable	11,285		24,619
Plant expenditures funded by deposits in NEEWS	0		-18,469
Deposits in New England East West Solution (NEEWS)	$0		$18,469
[1]	Information for segmenting total capital expenditures between Distribution and Transmission is not available. B Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.

BUSINESS_ORGANIZATION_AND_STAT

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2014
BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES [Abstract]	'
BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES	'
	(A)  BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES
	UIL Holdings is headquartered in New Haven, Connecticut, where its senior management maintains offices and is responsible for overall planning, operating and financial functions.  The primary business of UIL Holdings is ownership of its operating regulated utility businesses.  The utility businesses consist of the electric distribution and transmission operations of The United Illuminating Company (UI) and the natural gas transportation, distribution and sales operations of The Southern Connecticut Gas Company (SCG), Connecticut Natural Gas Corporation (CNG) and The Berkshire Gas Company (Berkshire, and together with SCG and CNG, the Gas Companies).
	UI is also a party to a joint venture with certain affiliates of NRG Energy, Inc. (NRG affiliates) pursuant to which UI holds 50% of the membership interests in GCE Holding LLC, whose wholly owned subsidiary, GenConn Energy LLC (collectively with GCE Holding LLC, GenConn) operates peaking generation plants in Devon, Connecticut (GenConn Devon) and Middletown, Connecticut (GenConn Middletown).
	Basis of Presentation
	The financial statements of UIL Holdings are prepared on a consolidated basis and therefore include the accounts of UIL Holdings’ majority-owned subsidiaries noted above.  Intercompany accounts and transactions have been eliminated in consolidation.  The year‑end balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (GAAP).  Certain information and footnote disclosures, which are normally included in financial statements prepared in accordance with GAAP, have been condensed or omitted in accordance with Securities and Exchange Commission (SEC) rules and regulations.  We believe that the disclosures made are adequate to make the information presented not misleading.  The information presented in the Consolidated Financial Statements reflects all adjustments which, in our opinion, are necessary for a fair statement of the financial position and results of operations for the interim periods described herein.  All such adjustments are of a normal and recurring nature.  The results for the three-month period ended March 31, 2014 are not necessarily indicative of the results for the entire fiscal year ending December 31, 2014.
	Certain immaterial amounts that were reported in the Consolidated Financial Statements in previous periods have been reclassified to conform to the current presentation.
	Philadelphia Gas Works
	On March 2, 2014, we entered into an Asset Purchase Agreement (Asset Purchase Agreement) with the City of Philadelphia pursuant to which UIL Holdings, through a wholly-owned subsidiary, will acquire the operating assets and assume certain liabilities of Philadelphia Gas Works (PGW) for an initial purchase price of $1.86 billion, subject to adjustment (the Acquisition).
	The Acquisition is subject to the satisfaction or waiver of certain customary and other closing conditions for transactions of this type, including approvals from the Philadelphia City Council and the Pennsylvania Public Utility Commission.  The Asset Purchase Agreement also contains termination provisions, including the right by either UIL Holdings or the City of Philadelphia to terminate the Asset Purchase Agreement if the Acquisition has not been consummated prior to March 31, 2015, subject to certain extension rights.  We may also terminate the Asset Purchase Agreement if the Philadelphia City Council has not enacted an ordinance approving the Acquisition by July 15, 2014, and the Asset Purchase Agreement will terminate automatically on December 31, 2014, if the Philadelphia City Council has not enacted an ordinance approving the Acquisition.  Subject to the approvals noted above, we expect to close the Acquisition by the end of the first quarter of 2015.
	As of March 31, 2014, UIL Holdings incurred pre-tax acquisition-related expenses of approximately $11.5 million, $5.1 million of which represents legal, investment banking, and due diligence costs that are included in operating expenses and $6.4 million of which is a fee associated with a Bridge Term Loan Agreement (Bridge Facility) that is included in other income and (deductions) in the Consolidated Statement of Income.  See Note (D) “Short-Term Credit Arrangements” for additional information about the Bridge Facility.
	Derivatives
	Our regulated subsidiaries are parties to contracts, and involved in transactions, that are derivatives.  The fair values of the gross derivative assets and liabilities as of March 31, 2014 and December 31, 2013 were as follows:
			March 31,			December 31,
			2014			2013
			(In Thousands)
	Gross derivative assets:
	Current Assets		$	9,073		$	9,098
	Deferred Charges and Other Assets		$	30,868		$	44,349
	Gross derivative liabilities:
	Current Liabilities		$	28,519		$	26,976
	Noncurrent Liabilities		$	81,374		$	169,327
	Contracts for Differences (CfDs)
	Pursuant to Connecticut’s 2005 Energy Independence Act, the Connecticut Public Utilities Regulatory Authority (PURA) solicited bids to create new or incremental capacity resources in order to reduce federally mandated congestion charges, and selected four new capacity resources.  To facilitate the transactions between the selected capacity resources and Connecticut electric customers, and provide the commitment necessary for owners of these resources to obtain necessary financing, PURA required that UI and The Connecticut Light and Power Company (CL&P) execute long-term contracts with the selected resources.  In August 2007, PURA approved four CfDs, each of which specifies a capacity quantity and a monthly settlement that reflects the difference between a forward market price and the contract price.  UI executed two of the contracts and CL&P executed the other two contracts.  The costs or benefits of each contract will be paid by or allocated to customers and will be subject to a cost-sharing agreement between UI and CL&P pursuant to which approximately 20% of the cost or benefit is borne by or allocated to UI customers and approximately 80% is borne by or allocated to CL&P customers.
	PURA has determined that costs associated with these CfDs will be fully recoverable by UI and CL&P through electric rates, and in accordance with ASC 980 “Regulated Operations,” UI has deferred recognition of costs (a regulatory asset) or obligations (a regulatory liability).  The CfDs are marked-to-market in accordance with ASC 815 “Derivatives and Hedging.”  For those CfDs signed by CL&P, UI records its approximate 20% portion pursuant to the cost-sharing agreement noted above.  As of March 31, 2014, UI has recorded a gross derivative asset of $39.9 million ($3.4 million of which is related to UI’s portion of CL&P’s derivative assets), a regulatory asset of $71.1 million, a gross derivative liability of $108.1 million ($62.5 million of which is related to UI’s portion of CL&P’s derivative liabilities) and a regulatory liability of $2.9 million  See Note (K) “Fair Value of Financial Instruments” for additional CfD information.
	The unrealized (gains) and losses from fair value adjustments to these derivatives recorded in regulatory assets or regulatory liabilities for the three month periods ended March 31, 2014 and 2013 were as follows:
			Three Months Ended
			March 31,
			2014			2013
			(In Thousands)
	Regulatory Assets - Derivative liabilities		$	(71,619	)	$	(8,165	)
	Regulatory Liabilities - Derivative assets		$	(2,942	)	$	-
	The increased unrealized gains in the three-month periods ended March 31, 2014 compared to March 31, 2013 are primarily due to increases in forward pricing.
	Weather Insurance Contracts
	On an annual basis, SCG and Berkshire each assess the need for weather insurance contracts for the upcoming heating season in order to provide financial protection from significant weather fluctuations.  According to the terms of such contracts, if temperatures are warmer than normal at a prescribed level for the contract period, a payment is received by the gas company; in addition, under certain of the contracts, if temperatures are colder than normal at a prescribed level for the contract period, the gas company is required to make a payment.  The premiums paid are amortized over the terms of the contracts.  The intrinsic value of the contracts is carried on the balance sheet with changes in value recorded in the income statement as Other Income and (Deductions).  As a result of PURA’s approval of a decoupling mechanism for CNG which went into effect in January 2014, CNG did not enter into a weather insurance contract for 2014.
	In October 2013, Berkshire entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014.  If temperatures are warmer than normal, Berkshire will receive a payment, up to a maximum of $1 million; however, if temperatures are colder than normal, Berkshire will make a payment of up to a maximum of $0.2 million.  The intrinsic value of the contract, which is carried on the balance sheet as a derivative liability, totaled $0.2 million at March 31, 2014.
	In September 2013, SCG entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014.  If temperatures are warmer than normal, SCG will receive a payment, up to a maximum of $3 million; however, if temperatures are colder than normal, SCG will make a payment of up to a maximum of $2 million.  The intrinsic value of the contract, which is carried on the balance sheet as a derivative liability, totaled $1.5 million at March 31, 2014.
	Earnings per Share
	The following table presents a reconciliation of the basic and diluted earnings per share calculations for the three-month periods ended March 31, 2014 and 2013:
			2014			2013
			(In Thousands, except per share amounts)
	Numerator:
	Net income attributable to UIL Holdings		$	55,452		$	51,791
	Less:  Net income allocated to unvested units			30			71
	Net income attributable to common shareholders		$	55,422		$	51,720
	Denominator:
	Basic average number of shares outstanding			56,779			50,888
	Effect of dilutive securities (1)			264			269
	Diluted average number of shares outstanding			57,043			51,157
	Earnings per share:
	Basic		$	0.98		$	1.02
	Diluted		$	0.97		$	1.01
	(1)  Includes unvested restricted stock and performance shares.
	Equity Investments
	UI is party to a 50-50 joint venture with NRG affiliates in GenConn, which operates two peaking generation plants in Connecticut.  UI’s investment in GenConn is being accounted for as an equity investment, the carrying value of which was $116.2 million and $118.2 million as of March 31, 2014 and December 31, 2013, respectively.  As of March 31, 2014, there was approximately $0.2 million of undistributed earnings from UI’s equity investment in GenConn.
	UI’s pre-tax income from its equity investment in GenConn was $3.4 million and $3.8 million for the three-month periods ending March 31, 2014 and 2013, respectively.
	Cash distributions from GenConn are reflected as either distributions of earnings or as returns of capital in the operating and investing sections of the Consolidated Statement of Cash Flows, respectively.  During the three-month period ending March 31, 2014, UI received cash distributions from GenConn of approximately $5.4 million.  UI did not receive any cash distributions from GenConn during the three month period ended March 31, 2013.
	Regulatory Accounting
	Unless otherwise stated below, all of our regulatory assets earn a return.  Our regulatory assets and liabilities as of March 31, 2014 and December 31, 2013 included the following:
		Remaining		March 31,			December 31,
		Period		2014			2013
				(In Thousands)
	Regulatory Assets:
	Nuclear plant investments – above market	(a)		$	238,868		$	238,868
Unamortized redemption costs	7 to 19 years			11,101			11,301
Pension and other post-retirement benefit plans	(b)			318,204			316,076
Environmental remediation costs	3 years			15,444			14,953
Hardship programs	(c)			21,696			25,019
Debt premium	1 to 24 years			32,809			34,178
Deferred purchased gas	(d)			-			2,556
Income taxes due principally to book-tax differences	(m)			151,190			149,015
Deferred income taxes	(e)			41,935			32,517
Contracts for differences	(f)			71,116			142,743
Excess generation service charge	(g)			11,542			6,909
Deferred transmission expense	(h)			8,719			9,615
Storm Costs	(i)			14,573			14,752
Other	(j)			26,849			37,628
Total regulatory assets				964,046			1,036,130
Less current portion of regulatory assets				326,262			332,391
Regulatory Assets, Net			$	637,784		$	703,739
Regulatory Liabilities:
Accumulated deferred investment tax credits	29 years		$	4,428		$	4,465
Income taxes due principally to book-tax differences	(m)			200,674			200,673
Deferred gain on sale of property	(a)			37,933			37,933
Middletown/Norwalk local transmission network service collections	35 years			21,258			21,402
Pension and other post-retirement benefit plans	6 years			26,094			27,686
Asset retirement obligation	(k)			6,793			5,593
Low income programs	(l)			28,488			25,300
Asset removal costs	(j)			325,375			319,530
Deferred income taxes	(e)			24,276			43,421
Contracts for differences	(f)			2,942			-
Deferred purchased gas	(d)			3,537			-
Non-firm margin sharing credits	10 years			24,667			-
Other	(j)			26,182			20,818
Total regulatory liabilities				732,647			706,821
Less current portion of regulatory liabilities				266,892			261,729
Regulatory Liabilities, Net			$	465,755		$	445,092
a) Asset/Liability relates to the Competitive Transition Assessment (CTA).  Total CTA costs recovery and stranded cost amortization are complete.  The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences.  As a result of the outcome of UI’s 2013 distribution rate request, PURA approved UI’s proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended.  The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet.
(b) Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) “Pension and Other Benefits” for additional information.
(c) Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
(d) Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
(e) The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
(f) Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability.  See “-Contracts for Differences” discussion above for additional information.
(g) Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
(h) Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
(i) Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the recovery of these costs.
(j) Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($6.6 million) and certain other amounts that are not currently earning a return.  See Note (C) “Regulatory Proceedings for a discussion of the decoupling recovery period.
(k) The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
(l) Various hardship and payment plan programs approved for recovery.
(m) Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA.  Due to the end of the CTA charge, the CTA regulatory liabilities are classified as current regulatory liabilities and the regulatory assets not related to the CTA are reclassified as long-term regulatory assets.
Stock-Based Compensation
Pursuant to the UIL Holdings 2008 Stock and Incentive Compensation Plan (2008 Stock Plan), a target amount of 123,940 performance shares were granted to certain members of management in March 2014; the average of the high and low market prices on the grant date, which approximates fair value, was $35.87 per share.
Also in March 2014, we granted a total of 2,196 shares of restricted stock to our President and Chief Executive Officer under the 2008 Stock Plan and in accordance with his employment agreement; the average of the high and low market price on the date of grant, which approximates fair value, was $35.87 per share.  Such shares vest in equal annual installments over a five-year period.
Total stock-based compensation expense for the three-month periods ended March 31, 2014 and 2013 was $2.5 million and $2.3 million, respectively.
Variable Interest Entities
We have identified GenConn as a variable interest entity (VIE), which is accounted for under the equity method.  UIL Holdings is not the primary beneficiary of GenConn, as defined in ASC 810 “Consolidation,” because it shares control of all significant activities of GenConn with its joint venturer, NRG affiliates.  As such, GenConn is not subject to consolidation.  GenConn recovers its costs through CfDs, which are cost of service-based and have been approved by PURA.  As a result, with the achievement of commercial operation by GenConn Devon and GenConn Middletown, our exposure to loss is primarily related to the potential for unrecovered GenConn operating or capital costs in a regulatory proceeding, the effect of which would be reflected in the carrying value of our 50% ownership position in GenConn and through “Income from Equity Investments” in UIL Holdings’ Consolidated Financial Statements.  Such exposure to loss cannot be determined at this time.  For further discussion of GenConn, see “–Equity Investments” as well as Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Equity Investment in Peaking Generation.”
We have identified the selected capacity resources with which UI has CfDs as VIEs and have concluded that UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these capacity resources.   As such, we have not consolidated the selected capacity resources.  UI’s maximum exposure to loss through these agreements is limited to the settlement amount under the CfDs as described in “–Derivatives – Contracts for Differences (CfDs)” above.  UI has no requirement to absorb additional losses nor has UI provided any financial or other support during the periods presented that were not previously contractually required.
We have identified the entities for which UI is required to enter into long-term contracts to purchase Renewable Energy Credits (RECs) as VIEs.  In assessing these contracts for VIE identification and reporting purposes, we have aggregated the contracts based on similar risk characteristics and significance to UI.  UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these entities.  UI’s exposure to loss is primarily related to the purchase and resale of the RECs, but, any losses incurred are recoverable through electric rates.  For further discussion of RECs, see Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – New Renewable Source Generation.”

CAPITALIZATION

CAPITALIZATION	3 Months Ended
	Mar. 31, 2014
CAPITALIZATION [Abstract]	'
CAPITALIZATION	'
	(B)  CAPITALIZATION
	Common Stock
	UIL Holdings had 56,532,748 shares of its common stock, no par value, outstanding at March 31, 2014.
	Preferred Stock of Subsidiaries, Noncontrolling Interests
	The preferred stock of subsidiaries is a noncontrolling interest because it contains a feature that allows the holders to elect a majority of the subsidiary’s board of directors if preferred stock dividends are in default in an amount equivalent to four full quarterly dividends.  Such a potential redemption-triggering event is not solely within the control of the subsidiary.
	CNG has one 8.00% non-callable series of cumulative preferred stock outstanding with a par value of $3.125 per share.  As of March 31, 2014, there were 108,706 shares issued and outstanding with a value of approximately $0.3 million and 775,609 shares authorized but unissued.
	On February 3, 2014, CTG Resources, Inc., CNG’s parent company, announced an offer to purchase all of the issued and outstanding shares of CNG’s $3.125 Par Preferred Stock for a purchase price of $7.50 per share.  The offer to purchase, which originally expired on March 4, 2014, has been extended to May 14, 2014 at an increased price of $10.25 per share, subject to the valid tender of at least two-thirds of the shares outstanding.

REGULATORY_PROCEEDINGS

REGULATORY PROCEEDINGS	3 Months Ended
	Mar. 31, 2014
REGULATORY PROCEEDINGS [Abstract]	'
REGULATORY PROCEEDINGS	'
	(C)  REGULATORY PROCEEDINGS
	Electric Distribution and Transmission
	Rates
	On February 15, 2013, UI filed an application to amend its existing distribution rate schedules for two rate years.  On August 14, 2013, PURA issued a decision (the August Decision) which became effective on that date and which, among other things, increased the UI distribution and CTA allowed return on equity (ROE) from 8.75% to 9.15%, continued UI’s existing earnings sharing mechanism by which UI and customers share on a 50/50 basis all distribution earnings above the allowed ROE in a calendar year, continued the existing decoupling mechanism, and approved the establishment of the requested storm reserve.  Additionally, the August Decision disallowed approximately $22 million related to deferred storm costs and capital costs related to UI’s recently constructed administrative and operations buildings.  As a result of these disallowances and other adjustments related to the rate proceeding, we recorded a one-time pre-tax write off of $17.5 million related to UI in the third quarter of 2013.
	On December 16, 2013, PURA issued a final decision on UI’s Petition for Reconsideration of the August Decision.  The final decision on the reconsideration restored approximately $6.8 million of deferred storm costs and approximately $2.7 million of capital costs related to UI’s recently constructed administrative and operations buildings which had been disallowed in the August Decision.  As a result, we recorded a one-time pre-tax adjustment of approximately $9.2 million in the fourth quarter of 2013 to reverse such amounts written off in the third quarter of 2013 as a result of the August Decision.  The resulting storm regulatory asset allowed for recovery totaled approximately $45 million.  PURA’s final determination on the timing of recovery of the remaining storm regulatory asset, if any, after applying the revenue from the 2010 and 2012 earnings sharing along with the excess CTA revenue collections is expected in the second half of 2014.  As of March 31, 2014, UI’s storm regulatory asset totaled approximately $14.6 million.
	Power Supply Arrangements
	UI has wholesale power supply agreements in place for its entire standard service load for the first half of 2014 and for 80% of its standard service load for the second half of 2014.  UI determined that its contracts for standard service and supplier of last resort service are derivatives under ASC 815 “Derivatives and Hedging” and elected the “normal purchase, normal sale” exception under ASC 815 “Derivatives and Hedging.”  UI regularly assesses the accounting treatment for its power supply contracts.  These wholesale power supply agreements contain default provisions that include required performance assurance, including certain collateral obligations, in the event that UI’s credit rating on senior debt were to fall below investment grade.  If UI’s credit rating were to decline one rating at Standard & Poor’s or two ratings at Moody’s and UI were to be placed on negative credit watch, monthly amounts due and payable to the power suppliers would be accelerated to semi-monthly payments.  UI’s credit rating would have to decline two ratings at Standard & Poor’s and three ratings at Moody’s to fall below investment grade.  If this were to occur, UI would have to deliver collateral security in an amount equal to the receivables due to the sellers for the thirty-day period immediately preceding the default notice.  If such an event had occurred as of March 31, 2014 UI would have had to post an aggregate of approximately $12 million in collateral.
	New Renewable Source Generation
	Under Connecticut Public Act No. 11-80, “An Act Concerning the Establishment of the Department of Energy and Environmental Protection and Planning for Connecticut's Energy Future” (PA 11-80), Connecticut electric utilities are required to enter into long-term contracts to purchase RECs from small renewable generators located on customer premises.  Under this program, UI is required to enter into contracts totaling approximately $200 million in commitments over an approximate 21-year period.  The obligations will phase in over a six-year solicitation period, and are expected to peak at an annual commitment level of about $13.6 million per year after all selected projects are online.  Upon purchase, UI accounts for the RECs as inventory.  UI expects to partially mitigate the cost of these contracts through the resale of the RECs.  PA 11-80 provides that the remaining costs (and any benefits) of these contracts, including any gain or loss resulting from the resale of the RECs, are fully recoverable from (or credited to) customers through electric rates.
	On October 23, 2013, PURA approved UI’s renewable connections program filed in accordance with PA 11-80, through which UI would develop up to 10 MW of renewable generation.  The costs for this program would be recovered on a cost of service basis.  In its approval, PURA established a base ROE to be calculated as the greater of:  (A) the current UI authorized distribution ROE plus 25 basis points and (B) the current authorized distribution ROE for CL&P, less target equivalent market revenues (reflected as 25 basis points).  In addition, UI will retain a percentage of the market revenues from the project, which percentage is expected to equate to approximately 25 basis points on a levelized basis over the life of the project.
	Section 6 of Connecticut Public Act 13-303, “An Act Concerning Connecticut’s Clean Energy Goals,” (PA 13-303), authorized DEEP to direct Connecticut’s electric distribution companies, including UI, to enter into contracts for energy and/or RECs from Class I renewable resources in a quantity of up to 4% of the electric distribution companies’ distribution load.  On July 8, 2013, DEEP issued a request for proposals (RFP), and directed UI and CL&P to enter into power purchase agreements with the winning bidders.  On September 19, 2013, UI entered into contracts with two of the winning bidders, totaling approximately 3.5% of UI’s distribution load, which were subsequently approved by PURA.  Costs of each of these agreements will be fully recoverable through electric rates.  On December 18, 2013, Allco Finance Limited, an unsuccessful bidder in the RFP, filed a complaint against DEEP in the United States District Court in Connecticut alleging that DEEP’s direction to UI and CL&P to enter into the contracts violated the Supremacy Clause of the U.S. Constitution and the Federal Power Act by setting wholesale electricity rates.  UI is not a party to the litigation.
	Section 8 of PA 13-303 authorized DEEP to direct Connecticut’s electric distribution companies, including UI, to enter into contracts for energy and/or RECs from biomass, landfill gas and small hydro projects that qualify as Connecticut Class I renewable resources in a quantity up to 4% of the electric distribution companies’ distribution load.  In January 2014, UI entered into three contracts for the purchase of RECs associated with an aggregate of 5.7 MW of energy production from biomass plants in New England as directed by DEEP.  The contracts are currently pending PURA approval.  PA 13‑303 provides that costs of any such agreements will be fully recoverable through electric rates.
	Transmission
	PURA decisions do not affect the revenue requirements determination for transmission, including the applicable return on equity (ROE), which are within the jurisdiction of the FERC.  For 2014, UI is estimating an overall allowed weighted-average ROE for its transmission business in the range of 12.1% to 12.3%.
	In September 2011, several New England governmental entities, including PURA, the Connecticut Attorney General and the Connecticut Office of Consumer Counsel, filed a joint complaint with the FERC against ISO-NE and several New England transmission owners, including UI, claiming that the current approved base ROE used in calculating formula rates for transmission service under the ISO-NE Open Access Transmission Tariff by the New England transmission owners  of 11.14% is not just and reasonable and seeking a proposed reduction of the base ROE to 9.20% to be effective for the period of October 1, 2011 through December 31, 2012.  A 25 basis point change in the weighted-average ROE for UI’s transmission business would change net income by approximately $0.6 million annually, for example.
	On August 6, 2013, the presiding Administrative Law Judge issued an initial decision finding that the existing base ROE was unjust and unreasonable, and that the just and reasonable base ROE is 10.6% for the refund period of October 1, 2011 through December 31, 2012 and, for the period after a final opinion is issued by the FERC,  9.7%, prior to any adjustments that may be applied by the FERC in a final order based on the change in 10-year U.S. Treasury Bond rates from the date hearings closed to the date of the FERC’s order.  We expect the FERC to issue its final opinion in 2014.  UI recorded a reserve for the refund period of $2.6 million during the third quarter based upon its assessment of the ultimate outcome of the proceeding.
	In December 2012, various additional parties filed a complaint with the FERC against several New England transmission owners, including UI, seeking a proposed reduction of the base ROE to 8.70%, effective December 27, 2012.  The transmission owners filed an answer and request for dismissal in January 2013, including opposition to the establishment of a second 15 month refund period, because the complaint seeks substantially the same relief against the same respondents but for a different 15 month period as the pending complaint of governmental entities.  The complainants filed their answer to the transmission owners’ answer in February 2013.  UI is unable to predict the outcome of this proceeding at this time.
	New England East-West Solution
	Pursuant to an agreement with CL&P (the Agreement), UI has the right to invest in, and own transmission assets associated with, the Connecticut portion of CL&P’s New England East West Solution (NEEWS) projects to improve regional energy reliability.  NEEWS consists of four inter-related transmission projects being developed by subsidiaries of Northeast Utilities (NU), the parent company of CL&P, in collaboration with National Grid USA.  Three of the projects have portions located in Connecticut:  (1) the Greater Springfield Reliability Project, which was fully energized in November 2013, (2) the Interstate Reliability Project, which is expected to be placed in service in late 2015 and (3) the Greater Hartford Central Connecticut Study (GHCC), which includes the reassessment of the Central Connecticut Reliability Project.  GHCC transmission solutions are being considered and a set of preferred solutions are expected to be identified by ISO-NE in the first half of 2014.
	Under the terms of the Agreement, UI has the option to make quarterly deposits to CL&P in exchange for ownership of specific NEEWS transmission assets as they are placed in service.  UI has the right to invest up to the greater of $60 million or an amount equal to 8.4% of CL&P’s costs for the Connecticut portions of the NEEWS projects.  Based upon the current projected costs, this amount is approximately $60 million.  As CL&P places assets in service, it will transfer title to certain NEEWS transmission assets to UI in proportion to UI’s investments, but CL&P will continue to maintain these portions of the transmission system pursuant to an operating and maintenance agreement (O&M Agreement) with UI.  Any termination of the Agreement pursuant to its terms would have no effect on the assets previously transferred to UI.
	Deposits associated with NEEWS are recorded as assets at the time the deposit is made and they are reported in the ‘Other’ line item within the Deferred Charges and Other Assets section of the consolidated balance sheet.   When title to the assets is transferred to UI, the amount of the corresponding deposit is reclassified from other assets to plant-in-service on the balance sheet and shown as a non-cash investing activity in the consolidated statement of cash flows.
	As of March 31, 2014, UI had made aggregate deposits of $36.1 million under the Agreement since its inception, with assets valued at approximately $24.6 million having been transferred to UI, as follows:  In September 2012, CL&P transferred approximately $6.2 million of transmission assets associated with the Greater Springfield Reliability Project, and in February 2013, CL&P transferred approximately $18.4 million of transmission assets, representing the remaining portion of the Greater Springfield Reliability Project.  UI earned pre-tax income on deposits, net of transferred assets, of approximately $0.3 million and $0.6 million in the three-month periods ended March 31, 2014 and 2013, respectively.  In May 2014, UI made an additional deposit of approximately $0.7 million.
	Equity Investment in Peaking Generation
	UI is party to a 50-50 joint venture with NRG affiliates in GenConn, which operates two peaking generation plants in Connecticut.  The two peaking generation plants, GenConn Devon and GenConn Middletown, are both participating in the ISO-New England markets.  PURA has approved revenue requirements for the period from January 1, 2014 through December 31, 2014 of $30.8 million and $37.5 million for GenConn Devon and GenConn Middletown, respectively.  In addition, PURA has ruled that GenConn project costs incurred that were in excess of the proposed costs originally submitted in 2008 were prudently incurred and are recoverable.  Such costs are included in the determination of the 2014 approved revenue requirements.
	Gas Distribution
	Rates
	The allowed returns on equity established by PURA are 9.18% and 9.36% for CNG and SCG, respectively.  Berkshire’s rates are established by the DPU.  Berkshire’s 10-year rate plan, which was approved by the DPU and included an approved ROE of 10.5%, expired on January 31, 2012.  Berkshire continues to charge the rates that were in effect at the end of the rate plan.  In response to a letter from the DPU requesting that Berkshire notify the DPU when Berkshire expected to file its next base distribution rate case and the test year for the filing, Berkshire responded that calendar year 2014 would be the earliest test year for a base rate case, and with such a test year a case would be filed by approximately May 15, 2015 with rates to be effective April 1, 2016.
	On July 8, 2013, CNG filed an application to amend its existing base delivery rate.  On January 22, 2014, PURA issued a final decision, with an effective date of January 10, 2014, which, among other things, approved an allowed ROE of 9.18%, a decoupling mechanism, and two separate ratemaking mechanisms that reconcile actual revenue requirements related to CNG’s cast iron and bare steel replacement program and system expansion.  Additionally, the final decision requires the establishment of an earnings sharing mechanism by which CNG and customers share on a 50/50 basis all earnings above the allowed ROE in a calendar year.  The decision also allows CNG, on a provisional basis, to reflect the increased rate base resulting from the accumulated deferred income tax (ADIT) impacts of the election of Section 338(h)(10) of the Internal Revenue Code upon its acquisition by UIL Holdings.   The decision requires CNG to seek a private letter ruling from the Internal Revenue Service with regard to the specific question of whether, after extinguishment of an ADIT balance, a directive by a public utility commission to institute a ratemaking mechanism to reflect a credit to ratepayers of ADIT benefits lost through a Section 338(h)(10) election would result in a normalization violation.  The decision states that in the event of a ruling from the Internal Revenue Service stating that imposing such a ratemaking mechanism would not create a normalization violation, PURA would adjust rates to offset the ratemaking impacts of the 338(h)(10) election on rate base.  We estimate the impact to be an approximate $2.5 to $3.5 million decrease in annual revenue requirements.  In March 2014, CNG filed a draft of its private letter ruling request with PURA for approval.  The Company is currently awaiting a response from PURA before submitting it to the Internal Revenue Service for ruling.  During the first quarter of 2014, the Office of Consumer Counsel appealed the decision to the Connecticut Superior Court with regard to the establishment of an adjustment mechanism for incremental cast iron and bare steel replacement as well as PURA’s directive to seek a private letter ruling with respect to the extinguishment of ADITs rather than ordering a rate credit to hold customers harmless from the ratemaking effect of extinguishing the ADITs.

SHORTTERM_CREDIT_ARRANGEMENTS

SHORT-TERM CREDIT ARRANGEMENTS	3 Months Ended
	Mar. 31, 2014
SHORT-TERM CREDIT ARRANGEMENTS [Abstract]	'
SHORT-TERM CREDIT ARRANGEMENTS	'
	(D)  SHORT‑TERM CREDIT ARRANGEMENTS
	As of March 31, 2014, there were no borrowings outstanding under the existing revolving credit agreement among UIL Holdings, certain of its subsidiaries and a group of banks, that expires on November 30, 2016 (the UIL Holdings Credit Facility).  Under the UIL Holdings Credit Facility, UIL Holdings has outstanding standby letters of credit in the aggregate amount of $4.4 million, which expire on June 16, 2014 and January 31, 2015.  Available credit under the UIL Holdings Credit Facility at March 31, 2014 totaled $395.6 million for UIL Holdings and its subsidiaries in the aggregate.  We record borrowings under the UIL Holdings Credit Facility as short‑term debt, but the UIL Holdings Credit Facility provides for longer term commitments from banks allowing us to borrow and reborrow funds, at our option, until the facility’s expiration, thus affording us flexibility in managing its working capital requirements.
	In connection with the Acquisition, on March 17, 2014, UIL Holdings and certain of its subsidiaries entered into an Amendment No. 1 to the UIL Holdings Credit Facility.  The purpose of the Amendment No. 1 was to address provisions that would be impacted by the Acquisition, including (i) amending the lien provisions to allow the existence of liens related to the Acquisition, (ii) amending the debt restrictions to allow UIL Holdings  to incur debt of up to $1.6 billion, subject to conditions and (iii) amending the debt covenant provisions to allow UIL Holdings and certain of its subsidiaries to maintain a ratio of Consolidated Debt to Consolidated Capital of not greater than 0.77 to 1.00, in connection with the Acquisition, subject to conditions.
	On March 28, 2014, in connection with the Acquisition, UIL Holdings and its subsidiary, WGP Acquisition LLC (WGP), entered into a 364-day Bridge Term Loan Agreement (Bridge Facility) with a group of banks and Morgan Stanley Senior Funding, Inc., as administrative agent in an aggregate principal amount of up to $1.9 billion.  Under the Bridge Facility, UIL Holdings may borrow the full amount and WGP may borrow up to $950 million, subject to the aggregate limit of $1.9 billion.  UIL Holdings and WGP will be severally liable for their respective borrowings.  Any undrawn commitments under the Bridge Facility will automatically be terminated on the date of the closing of the Acquisition.  As of March 31, 2014, there were no amounts outstanding under the Bridge Facility.

INCOME_TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2014
INCOME TAXES [Abstract]	'
INCOME TAXES	'
	(E) INCOME TAXES
	Differences in the treatment of certain transactions for book and tax purposes cause the rate of UIL Holdings’ reported income tax expense to differ from the statutory tax rate.  The annualized effective income tax rates for the three-month periods ended March 31, 2014 and 2013 were 33.4% and 36.9%, respectively.  The decrease in the effective tax rate is due primarily to the absence of non-normalized CTA amortization in 2014 as a result of the full amortization of these costs in 2013.
	The combined statutory federal and significant state income tax rate for UIL Holdings for the three-month periods ended March 31, 2014 and 2013 was 40.9%

SUPPLEMENTARY_INFORMATION

SUPPLEMENTARY INFORMATION	3 Months Ended
	Mar. 31, 2014
SUPPLEMENTARY INFORMATION [Abstract]	'
SUPPLEMENTARY INFORMATION	'
	(F)  SUPPLEMENTARY INFORMATION
		Three Months Ended
		March 31,
		2014			2013
		(In Thousands)
	Depreciation and Amortization
	Property, plant, and equipment depreciation	$	31,988		$	29,351
	Amortization of regulatory assets		8,330			20,756
	Total Depreciation and Amortization	$	40,318		$	50,107
	Taxes - Other than Income Taxes
	Operating:
	Connecticut gross earnings	$	22,714		$	21,964
	Local real estate and personal property		11,964			10,713
	Payroll taxes		3,857			2,793
	Other		1,001			396
	Total Taxes - Other than Income Taxes	$	39,536		$	35,866
	Other Income and (Deductions)
	Interest income	$	542		$	764
	Allowance for funds used during construction - equity		2,550			2,537
	Allowance for funds used during construction - debt		1,410			2,370
	Weather insurance		(1,906	)		24
	Other		1,266			(334	)
	Total Other Income and (Deductions)	$	3,862		$	5,361

PENSION_AND_OTHER_BENEFITS

PENSION AND OTHER BENEFITS	3 Months Ended
	Mar. 31, 2014
PENSION AND OTHER BENEFITS [Abstract]	'
PENSION AND OTHER BENEFITS	'
	(G)  PENSION AND OTHER BENEFITS
	During the three-months ended March 31, 2014, we made pension contributions of approximately $7.7 million.  Additional contributions during the remainder of 2014 are expected to be approximately $15.3 million in the aggregate.
	The following tables represent the components of net periodic benefit cost for pension and other postretirement benefits as well as the actuarial weighted-average assumptions used in calculating net periodic benefit cost for the three ‑month periods ended March 31, 2014 and 2013:
		Three Months Ended March 31,
		Pension Benefits						Other Postretirement Benefits
		2014			2013			2014			2013
		(In Thousands)
	Components of net periodic benefit cost:
	Service cost	$	2,896		$	3,696		$	404		$	481
	Interest cost		11,019			9,988			1,487			1,384
	Expected return on plan assets		(13,560	)		(12,863	)		(700	)		(648	)
	Amortization of:
	Prior service costs		73			151			71			(13	)
	Actuarial loss		3,097			5,208			(172	)		444
	Net periodic benefit cost	$	3,525		$	6,180		$	1,090		$	1,648
	Discount rate		4.90%-5.20	%		4.00%-4.25	%		4.85%-5.20	%		4.00%-4.25	%
	Average wage increase		3.50%-3.80	%		3.50%-3.80	%		N/	A		N/	A
	Return on plan assets		7.75%-8.00	%		7.75%-8.00	%		5.56%-8.00	%		5.56%-8.00	%
	Composite health care trend rate (current year)		N/	A		N/	A		7	%		7.5	%
	Composite health care trend rate (2018 forward)		N/	A		N/	A		5	%		5	%
	N/A – not applicable

RELATED_PARTY_TRANSACTIONS

RELATED PARTY TRANSACTIONS	3 Months Ended
	Mar. 31, 2014
RELATED PARTY TRANSACTIONS [Abstract]	'
RELATED PARTY TRANSACTIONS	'
	(H)  RELATED PARTY TRANSACTIONS
	A Director of UIL Holdings holds a beneficial interest in the building located at 157 Church Street, New Haven, Connecticut, where UIL Holdings leases office space.  UIL Holdings’ lease payments for this office space for the three‑month periods ended March 31, 2014 and 2013 totaled $0.5 million and $0.4 million, respectively.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2014
COMMITMENTS AND CONTINGENCIES [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	(J)  COMMITMENTS AND CONTINGENCIES
	In the ordinary course of business, we are involved in various proceedings, including legal, tax, regulatory and environmental matters, which require management’s assessment to determine the probability of whether a loss will occur and, if probable, an estimate of probable loss.  When assessments indicate that it is probable that a liability has been incurred and an amount can be reasonably estimated, we accrue a reserve and disclose the reserve and related matter.  We disclose material matters when losses are probable but for which an estimate cannot be reasonably estimated or when losses are not probable but are reasonably possible.  Subsequent analysis is performed on a periodic basis to assess the impact of any changes in events or circumstances and any resulting need to adjust existing reserves or record additional reserves.  However, given the inherent unpredictability of these legal and regulatory proceedings, we cannot assure you that our assessment of such proceedings will reflect the ultimate outcome, and an adverse outcome in certain matters could have a material adverse effect on our results of operations or cash flows.
	Connecticut Yankee Atomic Power Company
	UI has a 9.5% stock ownership share in the Connecticut Yankee Atomic Power Company, an inactive nuclear generating company (Connecticut Yankee), the carrying value of which was $0.1 million as of March 31, 2014.  Connecticut Yankee has completed the physical decommissioning of its generation facilities and is now engaged primarily in groundwater monitoring and in the long-term storage of its spent nuclear fuel. Connecticut Yankee collects its costs through wholesale FERC-approved rates from UI and several other New England utilities.  UI recovers these costs from its customers through retail rates.
	On May 1, 2013, Connecticut Yankee filed an application with FERC to, among other things, reduce its rates and eliminate future decommissioning funding requirements for its owners, using the United States Department of Energy (DOE) damage award, discussed below.  On June 27, 2013, FERC issued a final decision which approved both the proposed rate reduction and the elimination of future decommissioning funding requirements.  As a result, UI’s obligation and corresponding regulatory asset were eliminated at that time.
	DOE Spent Fuel Litigation
	In 1998, Connecticut Yankee filed claims in the United States Court of Federal Claims seeking damages resulting from the breach of the 1983 spent fuel and high level waste disposal contract between Connecticut Yankee and the DOE.  In September 2010, the court issued its decision and awarded Connecticut Yankee damages of $39.7 million for its spent fuel-related costs through 2001, which was affirmed in May 2012.  Connecticut Yankee received payment of the damage award and, in light of its ownership share, in July 2013 UI received approximately $3.8 million of such award was credited back to customers through the CTA.
	In December 2007, Connecticut Yankee filed a second set of complaints with the United States Court of Federal Claims against the DOE seeking damages incurred since January 1, 2002 for the DOE’s failure to remove Connecticut Yankee’s spent fuel.  In November 2013, the court issued a final judgment, which was not appealed, awarding Connecticut Yankee damages of $126.3 million.  In light of its ownership share, UI expects to receive approximately $12.0 million of such award in the first half of 2014 which would be refunded to customers.
	In August 2013, Connecticut Yankee filed a third set of complaints with the United States Court of Federal Claims against the DOE seeking unspecified damages incurred since January 1, 2009.
	Environmental Matters
	In complying with existing environmental statutes and regulations and further developments in areas of environmental concern, including legislation and studies in the fields of water quality, hazardous waste handling and disposal, toxic substances, climate change and electric and magnetic fields, we may incur substantial capital expenditures for equipment modifications and additions, monitoring equipment and recording devices, as well as additional operating expenses.  The total amount of these expenditures is not now determinable.  Environmental damage claims may also arise from the operations of our subsidiaries.  Significant environmental issues known to us at this time are described below.
	Site Decontamination, Demolition and Remediation Costs
	In 2000, UI conveyed a former generation site on the Mill River in New Haven (English Station) to an unaffiliated entity, Quinnipiac Energy LLC (QE), reserving to UI permanent easements for the operation of its transmission facilities on the site.  At the time of the sale, a fund of approximately $1.9 million, an amount equal to the then-current estimate for remediation, was placed in escrow for purposes of bringing soil and groundwater on the English Station site into compliance with applicable environmental laws.  As of March 31, 2014, approximately $0.1 million of the escrow fund remained.  In 2006, QE sold the property to Evergreen Power, LLC (Evergreen Power) and Asnat Realty LLC (Asnat).  In January 2012, Evergreen Power and Asnat filed a lawsuit in federal district court in Connecticut against UI seeking, among other things: (i) an order directing UI to reimburse the plaintiffs for costs they have incurred and will incur for the testing, investigating and remediation of hazardous substances at the English Station site and (ii) an order directing UI to investigate and remediate the site.  In May 2012, UI filed an answer and counterclaims.  In July 2012, Evergreen Power and Asnat filed a motion for partial summary judgment with respect to UI’s liability under the federal Comprehensive Environmental Response, Compensation, and Liability Act, which was denied without prejudice.  In December 2013, Evergreen and Asnat filed a subsequent lawsuit in Connecticut state court seeking among other things: (i) remediation of the property; (ii) reimbursement of remediation costs; (iii) termination of UI’s easement rights; (iv) reimbursement for costs associated with securing the property; and (v) punitive damages.  UI believes the claims are without merit.  UI’s knowledge of the current conditions at the English Station site is insufficient for it to make a reliable update of the original $1.9 million remediation estimate.  Management cannot presently assess the potential financial impact, if any, of the suits, and thus has not recorded a liability related to it and no amount of loss, if any, can be reasonably estimated at this time.
	On April 8, 2013, DEEP issued an administrative order addressed to UI, QE, Evergreen Power, Asnat and others, ordering the parties to take certain actions related to investigating and remediating the English Station site.  Mediation of the matter began in the fourth quarter of 2013 and is on-going.  At this time, management cannot predict the financial impact on UI of the DEEP order or other matters relating to this site and no amount of loss, if any, can be reasonably estimated at this time.
	In April 1999, UI completed the sale of its Bridgeport Harbor Station and New Haven Harbor Station generating plants in compliance with Connecticut’s electric utility industry restructuring legislation.  With respect to the portion of the New Haven Harbor Station site that UI retained, UI has performed an additional environmental analysis, indicating that approximately $3.2 million in remediation expenses will be incurred.  Actual remediation costs may be higher or lower than what is currently estimated.  The required remediation is virtually all on transmission‑related property and UI has accrued these estimated expenses, which were recovered in transmission rates.
	The Gas Companies own or have previously owned properties where Manufactured Gas Plants (MGPs) had historically operated.  MGP operations have led to contamination of soil and groundwater with petroleum hydrocarbons, benzene and metals, among other things, at these properties, the regulation and cleanup of which is regulated by the federal Resource Conservation and Recovery Act as well as other federal and state statutes and regulations.  Each of the Gas Companies has or had an ownership interest in one of such properties contaminated as a result of MGP-related activities.  Under the existing regulations, the cleanup of such sites requires state and at times, federal, regulators’ involvement and approval before cleanup can commence.  In certain cases, such contamination has been evaluated, characterized and remediated.  In other cases, the sites have been evaluated and characterized, but not yet remediated.  Finally, at some of these sites, the scope of the contamination has not yet been fully characterized; no liability was recorded in respect of these sites as of March 31, 2014 and no amount of loss, if any, can be reasonably estimated at this time.  In the past, the Gas Companies have received approval for the recovery of MGP-related remediation expenses from customers through rates and will seek recovery in rates for ongoing MGP-related remediation expenses for all of their MGP sites.
	SCG owns properties on Housatonic Avenue in Bridgeport, and on Chapel Street in New Haven, and CNG owns a property located on Columbus Boulevard in Hartford, all of which are former MGP sites.  Costs associated with the remediation of the sites could be significant and will be subject to a review by PURA as to whether these costs are recoverable in rates.  We cannot presently reasonably estimate the costs or range of costs of remediation or the likelihood of recoverability.  As a result, as of March 31, 2014, we have not recorded any liabilities related to these properties.
	Berkshire owns property on Mill Street in Greenfield, Massachusetts, a former MGP site.  We estimate that expenses associated with the remaining remedial activities, as well as the required ongoing monitoring and reporting to the Massachusetts Department of Environmental Protection will amount to approximately $2.9 million and have recorded a liability and offsetting regulatory asset for such expenses as of March 31, 2014.  Historically, Berkshire has received approval from the DPU for recovery of environmental expenses in its customer rates.
	Berkshire formerly owned a site on East Street (the East Street Site) in Pittsfield, Massachusetts, a former MGP site.  The East Street Site is part of a larger site known as the GE–Pittsfield/Housatonic River Site.  Berkshire sold the East Street Site to the General Electric Company (GE) in the 1970s and was named a potentially responsible party for the site by the EPA in 1990.  In December 2002, Berkshire reached a settlement with GE (the Settlement Agreement) which provides, among other things, a framework for Berkshire and GE to allocate various monitoring and remediation costs at the East Street Site.  As of March 31, 2014, we had accrued approximately $1.2 million and established a regulatory asset for these and future costs incurred by GE in responding to releases of hazardous substances at the East Street Site.  Historically, Berkshire has received approval from the DPU for recovery of remediation expenses in its customer rates.
	Middletown/Norwalk Transmission Project
	The general contractor and two subcontractors responsible for civil construction work in connection with the installation of UI’s portion of the Middletown/Norwalk Transmission Project’s underground electric cable system filed lawsuits in Connecticut state court on September 22, 2009, March 23, 2009 and January 25, 2010, respectively.  The claims, as revised by the general contractor in October 2011, sought payment for change order requests of approximately $33.3 million, a 10% general contractor mark-up on any approved subcontractor change order claims (approximately $2.3 million), interest, costs, and attorneys' fees.  In December 2011, UI settled claims brought by the two subcontractors and their respective lawsuits were dismissed with prejudice, reducing UI’s estimate of the general contractor’s claims to approximately $7.7 million, exclusive of the contractor’s claims for interest, costs, and attorneys’ fees.    UI also pursued an indemnification claim against the general contractor for the payments made in settlement to the two subcontractors.
	On September 3, 2013, a Memorandum of Decision was issued by the court finding for UI on all claims but one related to certain change orders, and ordering UI to pay the Contractor approximately $1.3 million.  The decision also found against UI on the indemnification claims.  On October 22, 2013, the general contractor filed an appeal of the Court’s ruling.  UI expects to recover any amounts paid to resolve the contractor and subcontractor claims through UI’s transmission revenue requirements.
	On April 30, 2013, an affiliate of the general contractor for the Middletown/Norwalk Transmission Project, purporting to act as a shareholder on behalf of UIL Holdings, filed a complaint against the UIL Holdings Board of Directors alleging that the directors breached a fiduciary duty by failing to undertake an independent investigation in response to a letter from the affiliate asking for an investigation regarding alleged improper practices by UI in connection with the Middletown/Norwalk Transmission Project.  On October 25, 2013, the court granted the defendants’ motion to dismiss the complaint. On November 15, 2013, the plaintiff filed an appeal of the court order in the Connecticut Appellate Court, which remains pending.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2014
FAIR VALUE MEASUREMENTS [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	(K) FAIR VALUE MEASUREMENTS
	As required by ASC 820 “Fair Value Measurements and Disclosures,” financial assets and liabilities are classified in their entirety, based on the lowest level of input that is significant to the fair value measurement.  Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels.
	The following tables set forth the fair value of our financial assets and liabilities, other than pension benefits and other postretirement benefits, as of March 31, 2014 and 2013.
			Fair Value Measurements Using
			Quoted Prices in			Significant			Significant			Total
			Active Markets			Other			Unobservable
			for Identical			Observable			Inputs (Level 3)
			Assets (Level 1)			Inputs (Level 2)
	31-Mar-14		(In Thousands)
	Assets:
	Derivative assets		$	-		$	-		$	39,941		$	39,941
	Noncurrent investments available for sale			11,318			-			-			11,318
	Deferred Compensation Plan			3,371			-			-			3,371
	Supplemental retirement benefit trust life insurance policies			-			7,976			-			7,976
			$	14,689		$	7,976		$	39,941		$	62,606
	Liabilities:
	Derivative liabilities		$	-		$	-		$	108,166		$	108,166
	Long-term debt			-			1,901,438			-			1,901,438
			$	-		$	1,901,438		$	108,166		$	2,009,604
	Net fair value assets/(liabilities), March 31, 2014		$	14,689		$	(1,893,462	)	$	(68,225	)	$	(1,946,998	)
	31-Dec-13
	Assets:
	Derivative assets		$	-		$	-		$	53,447		$	53,447
	Noncurrent investments available for sale			11,148			-			-			11,148
	Deferred Compensation Plan			3,775			-			-			3,775
	Supplemental retirement benefit trust life insurance policies			-			7,898			-			7,898
			$	14,923		$	7,898		$	53,447		$	76,268
	Liabilities:
	Derivative liabilities		$	-		$	-		$	196,233		$	196,233
	Long-term debt			-			1,846,867			-			1,846,867
			$	-		$	1,846,867		$	196,233		$	2,043,100
	Net fair value assets/(liabilities), December 31, 2013		$	14,923		$	(1,838,969	)	$	(142,786	)	$	(1,966,832	)
	Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements.  The derivative assets consist primarily of CfDs.  The determination of fair value of the CfDs was based on a probability-based expected cash flow analysis that was discounted at the March 31, 2014 or December 31, 2013 risk-free interest rates, as applicable, and an adjustment for non-performance risk using credit default swap rates.  Certain management assumptions were required, including development of pricing that extended over the term of the contracts.  We believe this methodology provides the most reasonable estimates of the amount of future discounted cash flows associated with the CfDs.  Additionally, on a quarterly basis, we perform analytics to ensure that the fair value of the derivatives is consistent with changes, if any, in the various fair value model inputs.  Additional quantitative information about Level 3 fair value measurements is as follows:
				Range at		Range at
		Unobservable Input		31-Mar-14		31-Dec-13
	Contracts for differences	Risk of non-performance		0.00% - 0.69%		0.00% - 0.62%
		Discount rate		1.73% - 2.88%		1.75% - 3.21%
		Forward pricing ($ per MW)		$2.95 - $14.59		$1.40 - $9.83
	Significant isolated changes in the risk of non-performance, the discount rate or the contract term pricing would result in an inverse change in the fair value of the CfDs.
	The determination of the fair value of the supplemental retirement benefit trust life insurance policies was based on quoted prices as of March 31, 2014 and December 31, 2013 in the active markets for the various funds within which the assets are held.
	Long-term debt is carried at cost on the consolidated balance sheet.  The fair value of long-term debt as displayed in the table above is based on evaluated prices that reflect significant observable market information such as reported trades, actual trade information of similar securities, benchmark yields, broker/dealer quotes of new issue prices and relevant credit information.
	The following tables set forth a reconciliation of changes in the fair value of the assets and liabilities above that are classified as Level 3 in the fair value hierarchy for the three-month period ended March 31, 2014.
			Three Months Ended
			31-Mar-14
			(In Thousands)
	Net derivative assets/(liabilities), December 31, 2013		$	(142,786	)
	Unrealized gains and (losses), net
	Included in earnings			-
	Included in regulatory assets/(liabilities)			74,561
	Settlements			-
	Net derivative assets/(liabilities), March 31, 2014		$	(68,225	)
	Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of March 31, 2014		$	74,561
	The following table sets forth a reconciliation of changes in the net regulatory asset/(liability) balances that were established to recover any unrealized gains/(losses) associated with the CfDs for the three-month period ended March 31, 2014.  The amounts offset the net CfDs liabilities included in the derivative liabilities detailed above.
			Three Months Ended
			31-Mar-14
			(In Thousands)
	Net regulatory assets/(liabilities), December 31, 2013		$	142,786
	Unrealized (gains) and losses, net			(74,561	)
	Net regulatory assets/(liabilities), March 31, 2014		$	68,225

SEGMENT_INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2014
SEGMENT INFORMATION [Abstract]	'
SEGMENT INFORMATION	'
	(M)  SEGMENT INFORMATION
	UIL Holdings is organized into Electric Distribution, Electric Transmission and Gas Distribution reporting segments based on several factors including, but not limited to, the nature of each segment’s products and services, the sources of operating revenues and expenses and the regulatory environment in which each segment operates.  The following measures of segment profit and loss are utilized by management to make decisions about allocating resources to the segments and assessing performance.  The following table reconciles certain segment information with that provided in our Consolidated Financial Statements.  In the table, distribution includes all electric utility revenue and expenses except for transmission, which is provided in a separate column.  “Other” includes the information for the remainder of our non‑utility activities and unallocated corporate costs, including minority interest investments and administrative costs.  Revenues from inter‑segment transactions are not material.  All of our revenues are derived in the United States.
	(In Thousands)
			Three months ended March 31, 2014
			Electric Distribution and Transmission						Gas Distribution
			Distribution		Transmission		Total					Other			Total
	Operating Revenues		$	145,189	$	58,788	$	203,977	$	367,185		$	-		$	571,162
	Purchased power and gas			53,130		-		53,130		214,925			-			268,055
	Operation and maintenance			45,817		10,581		56,398		39,656			(3,177	)		92,877
	Transmission wholesale			-		20,911		20,911		-			-			20,911
	Depreciation and amortization			12,063		4,225		16,288		21,748			2,282			40,318
	Taxes - other than income taxes			12,861		8,352		21,213		17,640			683			39,536
	Acquisition-related expenses			-		-		-		-			5,051			5,051
	Operating Income			21,318		14,719		36,037		73,216			(4,839	)		104,414
	Other Income and (Deductions), net			3,186		983		4,169		(981	)		(5,739	)		(2,551	)
	Interest Charges, net			7,832		3,204		11,036		6,763			5,435			23,234
	Income from Equity Investments			3,386		-		3,386		-			-			3,386
	Income (Loss) Before Income Taxes			20,058		12,498		32,556		65,472			(16,013	)		82,015
	Income Taxes			6,102		3,852		9,954		26,417			(9,821	)		26,550
	Net Income (Loss)			13,956		8,646		22,602		39,055			(6,192	)		55,465
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-		-		-		13			-			13
	Net Income (Loss) attributable to UIL Holdings		$	13,956	$	8,646	$	22,602	$	39,042		$	(6,192	)	$	55,452
	Total Capital Expenditures (1)		$	-	$	-	$	33,787	$	19,859		$	11,046		$	64,692
	(In Thousands)
			Three months ended March 31, 2013
			Electric Distribution and Transmission						Gas Distribution
			Distribution		Transmission		Total					Other			Total
	Operating Revenues		$	141,506	$	56,208	$	197,714	$	350,291		$	34		$	548,039
	Purchased power and gas			38,489		-		38,489		219,267			-			257,756
	Operation and maintenance			45,099		10,958		56,057		34,525			(1,323	)		89,259
	Transmission wholesale			-		18,818		18,818		-			-			18,818
	Depreciation and amortization			22,396		3,927		26,323		22,789			995			50,107
	Taxes - other than income taxes			12,139		7,311		19,450		16,196			220			35,866
	Operating Income			23,383		15,194		38,577		57,514			142			96,233
	Other Income and (Deductions), net			4,089		1,415		5,504		(857	)		714			5,361
	Interest Charges, net			6,940		3,128		10,068		7,196			6,048			23,312
	Income from Equity Investments			3,812		-		3,812		-			-			3,812
	Income (Loss) Before Income Taxes			24,344		13,481		37,825		49,461			(5,192	)		82,094
	Income Taxes			9,898		4,782		14,680		17,984			(2,377	)		30,287
	Net Income (Loss)			14,446		8,699		23,145		31,477			(2,815	)		51,807
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-		-		-		16			-			16
	Net Income (Loss) attributable to UIL Holdings		$	14,446	$	8,699	$	23,145	$	31,461		$	(2,815	)	$	51,791
	Total Capital Expenditures (1)		$	-	$	-	$	47,356	$	17,064		$	10,217		$	74,637
			Electric Distribution and Transmission (2)						Gas Distribution (3)
			Distribution		Transmission		Total					Other			Total (3)
	Total Assets at March 31, 2014		$	-	$	-	$	2,917,546	$	2,138,608		$	74,090		$	5,130,244
	Total Assets at December 31, 2013		$	-	$	-	$	2,950,707	$	2,010,246		$	183,267		$	5,144,220
	-1	Information for segmenting total capital expenditures between Distribution and Transmission is not available.  Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
	-2	Information for segmenting total assets between Distribution and Transmission is not available.  Total Electric Distribution and Transmission assets are disclosed in the Total Electric and Distribution and Transmission column.  Net plant in service is segregated by segment and, as of March 31, 2014, was $1,202.6 million and $660.7 million for Distribution and Transmission, respectively.  As of December 31, 2013, net plant in service was $1,181.1 million and $656.0 million for Distribution and Transmission, respectively.
	-3	Includes $266.2 million of goodwill in the Gas Distribution segment as of March 31, 2014 and December 31, 2013.

BUSINESS_ORGANIZATION_AND_STAT1

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2014
BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The financial statements of UIL Holdings are prepared on a consolidated basis and therefore include the accounts of UIL Holdings’ majority-owned subsidiaries noted above.  Intercompany accounts and transactions have been eliminated in consolidation.  The year‑end balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (GAAP).  Certain information and footnote disclosures, which are normally included in financial statements prepared in accordance with GAAP, have been condensed or omitted in accordance with Securities and Exchange Commission (SEC) rules and regulations.  We believe that the disclosures made are adequate to make the information presented not misleading.  The information presented in the Consolidated Financial Statements reflects all adjustments which, in our opinion, are necessary for a fair statement of the financial position and results of operations for the interim periods described herein.  All such adjustments are of a normal and recurring nature.  The results for the three-month period ended March 31, 2014 are not necessarily indicative of the results for the entire fiscal year ending December 31, 2014.
	Certain immaterial amounts that were reported in the Consolidated Financial Statements in previous periods have been reclassified to conform to the current presentation.
Philadelphia Gas Works	'
	Philadelphia Gas Works
	On March 2, 2014, we entered into an Asset Purchase Agreement (Asset Purchase Agreement) with the City of Philadelphia pursuant to which UIL Holdings, through a wholly-owned subsidiary, will acquire the operating assets and assume certain liabilities of Philadelphia Gas Works (PGW) for an initial purchase price of $1.86 billion, subject to adjustment (the Acquisition).
	The Acquisition is subject to the satisfaction or waiver of certain customary and other closing conditions for transactions of this type, including approvals from the Philadelphia City Council and the Pennsylvania Public Utility Commission.  The Asset Purchase Agreement also contains termination provisions, including the right by either UIL Holdings or the City of Philadelphia to terminate the Asset Purchase Agreement if the Acquisition has not been consummated prior to March 31, 2015, subject to certain extension rights.  We may also terminate the Asset Purchase Agreement if the Philadelphia City Council has not enacted an ordinance approving the Acquisition by July 15, 2014, and the Asset Purchase Agreement will terminate automatically on December 31, 2014, if the Philadelphia City Council has not enacted an ordinance approving the Acquisition.  Subject to the approvals noted above, we expect to close the Acquisition by the end of the first quarter of 2015.
	As of March 31, 2014, UIL Holdings incurred pre-tax acquisition-related expenses of approximately $11.5 million, $5.1 million of which represents legal, investment banking, and due diligence costs that are included in operating expenses and $6.4 million of which is a fee associated with a Bridge Term Loan Agreement (Bridge Facility) that is included in other income and (deductions) in the Consolidated Statement of Income.  See Note (D) “Short-Term Credit Arrangements” for additional information about the Bridge Facility.
Derivatives	'
	Derivatives
	Our regulated subsidiaries are parties to contracts, and involved in transactions, that are derivatives.  The fair values of the gross derivative assets and liabilities as of March 31, 2014 and December 31, 2013 were as follows:
			March 31,			December 31,
			2014			2013
			(In Thousands)
	Gross derivative assets:
	Current Assets		$	9,073		$	9,098
	Deferred Charges and Other Assets		$	30,868		$	44,349
	Gross derivative liabilities:
	Current Liabilities		$	28,519		$	26,976
	Noncurrent Liabilities		$	81,374		$	169,327
	Contracts for Differences (CfDs)
	Pursuant to Connecticut’s 2005 Energy Independence Act, the Connecticut Public Utilities Regulatory Authority (PURA) solicited bids to create new or incremental capacity resources in order to reduce federally mandated congestion charges, and selected four new capacity resources.  To facilitate the transactions between the selected capacity resources and Connecticut electric customers, and provide the commitment necessary for owners of these resources to obtain necessary financing, PURA required that UI and The Connecticut Light and Power Company (CL&P) execute long-term contracts with the selected resources.  In August 2007, PURA approved four CfDs, each of which specifies a capacity quantity and a monthly settlement that reflects the difference between a forward market price and the contract price.  UI executed two of the contracts and CL&P executed the other two contracts.  The costs or benefits of each contract will be paid by or allocated to customers and will be subject to a cost-sharing agreement between UI and CL&P pursuant to which approximately 20% of the cost or benefit is borne by or allocated to UI customers and approximately 80% is borne by or allocated to CL&P customers.
	PURA has determined that costs associated with these CfDs will be fully recoverable by UI and CL&P through electric rates, and in accordance with ASC 980 “Regulated Operations,” UI has deferred recognition of costs (a regulatory asset) or obligations (a regulatory liability).  The CfDs are marked-to-market in accordance with ASC 815 “Derivatives and Hedging.”  For those CfDs signed by CL&P, UI records its approximate 20% portion pursuant to the cost-sharing agreement noted above.  As of March 31, 2014, UI has recorded a gross derivative asset of $39.9 million ($3.4 million of which is related to UI’s portion of CL&P’s derivative assets), a regulatory asset of $71.1 million, a gross derivative liability of $108.1 million ($62.5 million of which is related to UI’s portion of CL&P’s derivative liabilities) and a regulatory liability of $2.9 million  See Note (K) “Fair Value of Financial Instruments” for additional CfD information.
	The unrealized (gains) and losses from fair value adjustments to these derivatives recorded in regulatory assets or regulatory liabilities for the three month periods ended March 31, 2014 and 2013 were as follows:
			Three Months Ended
			March 31,
			2014			2013
			(In Thousands)
	Regulatory Assets - Derivative liabilities		$	(71,619	)	$	(8,165	)
	Regulatory Liabilities - Derivative assets		$	(2,942	)	$	-
	The increased unrealized gains in the three-month periods ended March 31, 2014 compared to March 31, 2013 are primarily due to increases in forward pricing.
	Weather Insurance Contracts
	On an annual basis, SCG and Berkshire each assess the need for weather insurance contracts for the upcoming heating season in order to provide financial protection from significant weather fluctuations.  According to the terms of such contracts, if temperatures are warmer than normal at a prescribed level for the contract period, a payment is received by the gas company; in addition, under certain of the contracts, if temperatures are colder than normal at a prescribed level for the contract period, the gas company is required to make a payment.  The premiums paid are amortized over the terms of the contracts.  The intrinsic value of the contracts is carried on the balance sheet with changes in value recorded in the income statement as Other Income and (Deductions).  As a result of PURA’s approval of a decoupling mechanism for CNG which went into effect in January 2014, CNG did not enter into a weather insurance contract for 2014.
	In October 2013, Berkshire entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014.  If temperatures are warmer than normal, Berkshire will receive a payment, up to a maximum of $1 million; however, if temperatures are colder than normal, Berkshire will make a payment of up to a maximum of $0.2 million.  The intrinsic value of the contract, which is carried on the balance sheet as a derivative liability, totaled $0.2 million at March 31, 2014.
	In September 2013, SCG entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014.  If temperatures are warmer than normal, SCG will receive a payment, up to a maximum of $3 million; however, if temperatures are colder than normal, SCG will make a payment of up to a maximum of $2 million.  The intrinsic value of the contract, which is carried on the balance sheet as a derivative liability, totaled $1.5 million at March 31, 2014.
Earnings per Share	'
	Earnings per Share
	The following table presents a reconciliation of the basic and diluted earnings per share calculations for the three-month periods ended March 31, 2014 and 2013:
			2014			2013
			(In Thousands, except per share amounts)
	Numerator:
	Net income attributable to UIL Holdings		$	55,452		$	51,791
	Less:  Net income allocated to unvested units			30			71
	Net income attributable to common shareholders		$	55,422		$	51,720
	Denominator:
	Basic average number of shares outstanding			56,779			50,888
	Effect of dilutive securities (1)			264			269
	Diluted average number of shares outstanding			57,043			51,157
	Earnings per share:
	Basic		$	0.98		$	1.02
	Diluted		$	0.97		$	1.01
	(1)  Includes unvested restricted stock and performance shares.
Equity Investments	'
	Equity Investments
	UI is party to a 50-50 joint venture with NRG affiliates in GenConn, which operates two peaking generation plants in Connecticut.  UI’s investment in GenConn is being accounted for as an equity investment, the carrying value of which was $116.2 million and $118.2 million as of March 31, 2014 and December 31, 2013, respectively.  As of March 31, 2014, there was approximately $0.2 million of undistributed earnings from UI’s equity investment in GenConn.
	UI’s pre-tax income from its equity investment in GenConn was $3.4 million and $3.8 million for the three-month periods ending March 31, 2014 and 2013, respectively.
	Cash distributions from GenConn are reflected as either distributions of earnings or as returns of capital in the operating and investing sections of the Consolidated Statement of Cash Flows, respectively.  During the three-month period ending March 31, 2014, UI received cash distributions from GenConn of approximately $5.4 million.  UI did not receive any cash distributions from GenConn during the three month period ended March 31, 2013.
Regulatory Accounting	'
	Regulatory Accounting
	Unless otherwise stated below, all of our regulatory assets earn a return.  Our regulatory assets and liabilities as of March 31, 2014 and December 31, 2013 included the following:
		Remaining		March 31,			December 31,
		Period		2014			2013
				(In Thousands)
	Regulatory Assets:
	Nuclear plant investments – above market	(a)		$	238,868		$	238,868
	Unamortized redemption costs	7 to 19 years			11,101			11,301
	Pension and other post-retirement benefit plans	(b)			318,204			316,076
	Environmental remediation costs	3 years			15,444			14,953
	Hardship programs	(c)			21,696			25,019
	Debt premium	1 to 24 years			32,809			34,178
	Deferred purchased gas	(d)			-			2,556
	Income taxes due principally to book-tax differences	(m)			151,190			149,015
	Deferred income taxes	(e)			41,935			32,517
	Contracts for differences	(f)			71,116			142,743
	Excess generation service charge	(g)			11,542			6,909
	Deferred transmission expense	(h)			8,719			9,615
	Storm Costs	(i)			14,573			14,752
	Other	(j)			26,849			37,628
	Total regulatory assets				964,046			1,036,130
	Less current portion of regulatory assets				326,262			332,391
	Regulatory Assets, Net			$	637,784		$	703,739
	Regulatory Liabilities:
	Accumulated deferred investment tax credits	29 years		$	4,428		$	4,465
	Income taxes due principally to book-tax differences	(m)			200,674			200,673
	Deferred gain on sale of property	(a)			37,933			37,933
	Middletown/Norwalk local transmission network service collections	35 years			21,258			21,402
	Pension and other post-retirement benefit plans	6 years			26,094			27,686
	Asset retirement obligation	(k)			6,793			5,593
	Low income programs	(l)			28,488			25,300
	Asset removal costs	(j)			325,375			319,530
	Deferred income taxes	(e)			24,276			43,421
	Contracts for differences	(f)			2,942			-
	Deferred purchased gas	(d)			3,537			-
	Non-firm margin sharing credits	10 years			24,667			-
	Other	(j)			26,182			20,818
	Total regulatory liabilities				732,647			706,821
	Less current portion of regulatory liabilities				266,892			261,729
	Regulatory Liabilities, Net			$	465,755		$	445,092
	a) Asset/Liability relates to the Competitive Transition Assessment (CTA).  Total CTA costs recovery and stranded cost amortization are complete.  The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences.  As a result of the outcome of UI’s 2013 distribution rate request, PURA approved UI’s proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended.  The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet.
	(b) Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) “Pension and Other Benefits” for additional information.
	(c) Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
	(d) Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
	(e) The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
	(f) Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability.  See “-Contracts for Differences” discussion above for additional information.
	(g) Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
	(h) Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
	(i) Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the recovery of these costs.
	(j) Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($6.6 million) and certain other amounts that are not currently earning a return.  See Note (C) “Regulatory Proceedings for a discussion of the decoupling recovery period.
	(k) The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
	(l) Various hardship and payment plan programs approved for recovery.
	(m) Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA.  Due to the end of the CTA charge, the CTA regulatory liabilities are classified as current regulatory liabilities and the regulatory assets not related to the CTA are reclassified as long-term regulatory assets.
Stock-Based Compensation	'
	Stock-Based Compensation
	Pursuant to the UIL Holdings 2008 Stock and Incentive Compensation Plan (2008 Stock Plan), a target amount of 123,940 performance shares were granted to certain members of management in March 2014; the average of the high and low market prices on the grant date, which approximates fair value, was $35.87 per share.
	Also in March 2014, we granted a total of 2,196 shares of restricted stock to our President and Chief Executive Officer under the 2008 Stock Plan and in accordance with his employment agreement; the average of the high and low market price on the date of grant, which approximates fair value, was $35.87 per share.  Such shares vest in equal annual installments over a five-year period.
	Total stock-based compensation expense for the three-month periods ended March 31, 2014 and 2013 was $2.5 million and $2.3 million, respectively.
Variable Interest Entities	'
	Variable Interest Entities
	We have identified GenConn as a variable interest entity (VIE), which is accounted for under the equity method.  UIL Holdings is not the primary beneficiary of GenConn, as defined in ASC 810 “Consolidation,” because it shares control of all significant activities of GenConn with its joint venturer, NRG affiliates.  As such, GenConn is not subject to consolidation.  GenConn recovers its costs through CfDs, which are cost of service-based and have been approved by PURA.  As a result, with the achievement of commercial operation by GenConn Devon and GenConn Middletown, our exposure to loss is primarily related to the potential for unrecovered GenConn operating or capital costs in a regulatory proceeding, the effect of which would be reflected in the carrying value of our 50% ownership position in GenConn and through “Income from Equity Investments” in UIL Holdings’ Consolidated Financial Statements.  Such exposure to loss cannot be determined at this time.  For further discussion of GenConn, see “–Equity Investments” as well as Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Equity Investment in Peaking Generation.”
	We have identified the selected capacity resources with which UI has CfDs as VIEs and have concluded that UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these capacity resources.   As such, we have not consolidated the selected capacity resources.  UI’s maximum exposure to loss through these agreements is limited to the settlement amount under the CfDs as described in “–Derivatives – Contracts for Differences (CfDs)” above.  UI has no requirement to absorb additional losses nor has UI provided any financial or other support during the periods presented that were not previously contractually required.
	We have identified the entities for which UI is required to enter into long-term contracts to purchase Renewable Energy Credits (RECs) as VIEs.  In assessing these contracts for VIE identification and reporting purposes, we have aggregated the contracts based on similar risk characteristics and significance to UI.  UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these entities.  UI’s exposure to loss is primarily related to the purchase and resale of the RECs, but, any losses incurred are recoverable through electric rates.  For further discussion of RECs, see Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – New Renewable Source Generation.”

BUSINESS_ORGANIZATION_AND_STAT2

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2014
BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES [Abstract]	'
Value of Gross Derivative Assets and Liabilities	'
	Our regulated subsidiaries are parties to contracts, and involved in transactions, that are derivatives.  The fair values of the gross derivative assets and liabilities as of March 31, 2014 and December 31, 2013 were as follows:
			March 31,			December 31,
			2014			2013
			(In Thousands)
	Gross derivative assets:
	Current Assets		$	9,073		$	9,098
	Deferred Charges and Other Assets		$	30,868		$	44,349
	Gross derivative liabilities:
	Current Liabilities		$	28,519		$	26,976
	Noncurrent Liabilities		$	81,374		$	169,327
Unrealized Gains and Losses From Mark-To-Market Adjustments	'
	The unrealized (gains) and losses from fair value adjustments to these derivatives recorded in regulatory assets or regulatory liabilities for the three month periods ended March 31, 2014 and 2013 were as follows:
			Three Months Ended
			March 31,
			2014			2013
			(In Thousands)
	Regulatory Assets - Derivative liabilities		$	(71,619	)	$	(8,165	)
	Regulatory Liabilities - Derivative assets		$	(2,942	)	$	-
Reconciliation of Basic and Diluted Earnings Per Share	'
	The following table presents a reconciliation of the basic and diluted earnings per share calculations for the three-month periods ended March 31, 2014 and 2013:
			2014			2013
			(In Thousands, except per share amounts)
	Numerator:
	Net income attributable to UIL Holdings		$	55,452		$	51,791
	Less:  Net income allocated to unvested units			30			71
	Net income attributable to common shareholders		$	55,422		$	51,720
	Denominator:
	Basic average number of shares outstanding			56,779			50,888
	Effect of dilutive securities (1)			264			269
	Diluted average number of shares outstanding			57,043			51,157
	Earnings per share:
	Basic		$	0.98		$	1.02
	Diluted		$	0.97		$	1.01
	(1)  Includes unvested restricted stock and performance shares.
Regulatory Assets and Liabilities	'
	Unless otherwise stated below, all of our regulatory assets earn a return.  Our regulatory assets and liabilities as of March 31, 2014 and December 31, 2013 included the following:
		Remaining		March 31,			December 31,
		Period		2014			2013
				(In Thousands)
	Regulatory Assets:
	Nuclear plant investments – above market	(a)		$	238,868		$	238,868
	Unamortized redemption costs	7 to 19 years			11,101			11,301
	Pension and other post-retirement benefit plans	(b)			318,204			316,076
	Environmental remediation costs	3 years			15,444			14,953
	Hardship programs	(c)			21,696			25,019
	Debt premium	1 to 24 years			32,809			34,178
	Deferred purchased gas	(d)			-			2,556
	Income taxes due principally to book-tax differences	(m)			151,190			149,015
	Deferred income taxes	(e)			41,935			32,517
	Contracts for differences	(f)			71,116			142,743
	Excess generation service charge	(g)			11,542			6,909
	Deferred transmission expense	(h)			8,719			9,615
	Storm Costs	(i)			14,573			14,752
	Other	(j)			26,849			37,628
	Total regulatory assets				964,046			1,036,130
	Less current portion of regulatory assets				326,262			332,391
	Regulatory Assets, Net			$	637,784		$	703,739
	Regulatory Liabilities:
	Accumulated deferred investment tax credits	29 years		$	4,428		$	4,465
	Income taxes due principally to book-tax differences	(m)			200,674			200,673
	Deferred gain on sale of property	(a)			37,933			37,933
	Middletown/Norwalk local transmission network service collections	35 years			21,258			21,402
	Pension and other post-retirement benefit plans	6 years			26,094			27,686
	Asset retirement obligation	(k)			6,793			5,593
	Low income programs	(l)			28,488			25,300
	Asset removal costs	(j)			325,375			319,530
	Deferred income taxes	(e)			24,276			43,421
	Contracts for differences	(f)			2,942			-
	Deferred purchased gas	(d)			3,537			-
	Non-firm margin sharing credits	10 years			24,667			-
	Other	(j)			26,182			20,818
	Total regulatory liabilities				732,647			706,821
	Less current portion of regulatory liabilities				266,892			261,729
	Regulatory Liabilities, Net			$	465,755		$	445,092
	a) Asset/Liability relates to the Competitive Transition Assessment (CTA).  Total CTA costs recovery and stranded cost amortization are complete.  The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences.  As a result of the outcome of UI’s 2013 distribution rate request, PURA approved UI’s proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended.  The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet.
	(b) Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) “Pension and Other Benefits” for additional information.
	(c) Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
	(d) Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
	(e) The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
	(f) Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability.  See “-Contracts for Differences” discussion above for additional information.
	(g) Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
	(h) Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
	(i) Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the recovery of these costs.
	(j) Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($6.6 million) and certain other amounts that are not currently earning a return.  See Note (C) “Regulatory Proceedings for a discussion of the decoupling recovery period.
	(k) The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
	(l) Various hardship and payment plan programs approved for recovery.
	(m) Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA.  Due to the end of the CTA charge, the CTA regulatory liabilities are classified as current regulatory liabilities and the regulatory assets not related to the CTA are reclassified as long-term regulatory assets.

SUPPLEMENTARY_INFORMATION_Tabl

SUPPLEMENTARY INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2014
SUPPLEMENTARY INFORMATION [Abstract]	'
Supplementary Information	'
	SUPPLEMENTARY INFORMATION
		Three Months Ended
		March 31,
		2014			2013
		(In Thousands)
	Depreciation and Amortization
	Property, plant, and equipment depreciation	$	31,988		$	29,351
	Amortization of regulatory assets		8,330			20,756
	Total Depreciation and Amortization	$	40,318		$	50,107
	Taxes - Other than Income Taxes
	Operating:
	Connecticut gross earnings	$	22,714		$	21,964
	Local real estate and personal property		11,964			10,713
	Payroll taxes		3,857			2,793
	Other		1,001			396
	Total Taxes - Other than Income Taxes	$	39,536		$	35,866
	Other Income and (Deductions)
	Interest income	$	542		$	764
	Allowance for funds used during construction - equity		2,550			2,537
	Allowance for funds used during construction - debt		1,410			2,370
	Weather insurance		(1,906	)		24
	Other		1,266			(334	)
	Total Other Income and (Deductions)	$	3,862		$	5,361

PENSION_AND_OTHER_BENEFITS_Tab

PENSION AND OTHER BENEFITS (Tables)	3 Months Ended
	Mar. 31, 2014
PENSION AND OTHER BENEFITS [Abstract]	'
Components of Net Periodic Benefit Cost for Pension and Other Postretirement Benefits	'
	The following tables represent the components of net periodic benefit cost for pension and other postretirement benefits as well as the actuarial weighted-average assumptions used in calculating net periodic benefit cost for the three ‑month periods ended March 31, 2014 and 2013:
		Three Months Ended March 31,
		Pension Benefits						Other Postretirement Benefits
		2014			2013			2014			2013
		(In Thousands)
	Components of net periodic benefit cost:
	Service cost	$	2,896		$	3,696		$	404		$	481
	Interest cost		11,019			9,988			1,487			1,384
	Expected return on plan assets		(13,560	)		(12,863	)		(700	)		(648	)
	Amortization of:
	Prior service costs		73			151			71			(13	)
	Actuarial loss		3,097			5,208			(172	)		444
	Net periodic benefit cost	$	3,525		$	6,180		$	1,090		$	1,648
Weighted Average Actuarial Assumption used in Calculating Net Periodic Benefit Cost	'
	Discount rate		4.90%-5.20	%		4.00%-4.25	%		4.85%-5.20	%		4.00%-4.25	%
	Average wage increase		3.50%-3.80	%		3.50%-3.80	%		N/	A		N/	A
	Return on plan assets		7.75%-8.00	%		7.75%-8.00	%		5.56%-8.00	%		5.56%-8.00	%
	Composite health care trend rate (current year)		N/	A		N/	A		7	%		7.5	%
	Composite health care trend rate (2018 forward)		N/	A		N/	A		5	%		5	%

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2014
FAIR VALUE MEASUREMENTS [Abstract]	'
Fair Value of Financial Assets and Liabilities	'
	The following tables set forth the fair value of our financial assets and liabilities, other than pension benefits and other postretirement benefits, as of March 31, 2014 and 2013.
			Fair Value Measurements Using
			Quoted Prices in			Significant			Significant			Total
			Active Markets			Other			Unobservable
			for Identical			Observable			Inputs (Level 3)
			Assets (Level 1)			Inputs (Level 2)
	31-Mar-14		(In Thousands)
	Assets:
	Derivative assets		$	-		$	-		$	39,941		$	39,941
	Noncurrent investments available for sale			11,318			-			-			11,318
	Deferred Compensation Plan			3,371			-			-			3,371
	Supplemental retirement benefit trust life insurance policies			-			7,976			-			7,976
			$	14,689		$	7,976		$	39,941		$	62,606
	Liabilities:
	Derivative liabilities		$	-		$	-		$	108,166		$	108,166
	Long-term debt			-			1,901,438			-			1,901,438
			$	-		$	1,901,438		$	108,166		$	2,009,604
	Net fair value assets/(liabilities), March 31, 2014		$	14,689		$	(1,893,462	)	$	(68,225	)	$	(1,946,998	)
	31-Dec-13
	Assets:
	Derivative assets		$	-		$	-		$	53,447		$	53,447
	Noncurrent investments available for sale			11,148			-			-			11,148
	Deferred Compensation Plan			3,775			-			-			3,775
	Supplemental retirement benefit trust life insurance policies			-			7,898			-			7,898
			$	14,923		$	7,898		$	53,447		$	76,268
	Liabilities:
	Derivative liabilities		$	-		$	-		$	196,233		$	196,233
	Long-term debt			-			1,846,867			-			1,846,867
			$	-		$	1,846,867		$	196,233		$	2,043,100
	Net fair value assets/(liabilities), December 31, 2013		$	14,923		$	(1,838,969	)	$	(142,786	)	$	(1,966,832	)
Additional Quantitative Information about Level 3 Fair Value Measurements	'
	Additional quantitative information about Level 3 fair value measurements is as follows:
				Range at		Range at
		Unobservable Input		31-Mar-14		31-Dec-13
	Contracts for differences	Risk of non-performance		0.00% - 0.69%		0.00% - 0.62%
		Discount rate		1.73% - 2.88%		1.75% - 3.21%
		Forward pricing ($ per MW)		$2.95 - $14.59		$1.40 - $9.83
Changes in Fair Value of Assets and Liabilities Classified as level 3	'
	The following tables set forth a reconciliation of changes in the fair value of the assets and liabilities above that are classified as Level 3 in the fair value hierarchy for the three-month period ended March 31, 2014.
			Three Months Ended
			31-Mar-14
			(In Thousands)
	Net derivative assets/(liabilities), December 31, 2013		$	(142,786	)
	Unrealized gains and (losses), net
	Included in earnings			-
	Included in regulatory assets/(liabilities)			74,561
	Settlements			-
	Net derivative assets/(liabilities), March 31, 2014		$	(68,225	)
	Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of March 31, 2014		$	74,561
Change in Regulatory Asset/(Liability) Balance	'
	The amounts offset the net CfDs liabilities included in the derivative liabilities detailed above.
			Three Months Ended
			31-Mar-14
			(In Thousands)
	Net regulatory assets/(liabilities), December 31, 2013		$	142,786
	Unrealized (gains) and losses, net			(74,561	)
	Net regulatory assets/(liabilities), March 31, 2014		$	68,225

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2014
SEGMENT INFORMATION [Abstract]	'
Reconciliation of Operating Profit (Loss) from Segments to Consolidated Financial Statements	'
	The following table reconciles certain segment information with that provided in our Consolidated Financial Statements.  In the table, distribution includes all electric utility revenue and expenses except for transmission, which is provided in a separate column.  “Other” includes the information for the remainder of our non‑utility activities and unallocated corporate costs, including minority interest investments and administrative costs.  Revenues from inter‑segment transactions are not material.  All of our revenues are derived in the United States.
	(In Thousands)
			Three months ended March 31, 2014
			Electric Distribution and Transmission						Gas Distribution
			Distribution		Transmission		Total					Other			Total
	Operating Revenues		$	145,189	$	58,788	$	203,977	$	367,185		$	-		$	571,162
	Purchased power and gas			53,130		-		53,130		214,925			-			268,055
	Operation and maintenance			45,817		10,581		56,398		39,656			(3,177	)		92,877
	Transmission wholesale			-		20,911		20,911		-			-			20,911
	Depreciation and amortization			12,063		4,225		16,288		21,748			2,282			40,318
	Taxes - other than income taxes			12,861		8,352		21,213		17,640			683			39,536
	Acquisition-related expenses			-		-		-		-			5,051			5,051
	Operating Income			21,318		14,719		36,037		73,216			(4,839	)		104,414
	Other Income and (Deductions), net			3,186		983		4,169		(981	)		(5,739	)		(2,551	)
	Interest Charges, net			7,832		3,204		11,036		6,763			5,435			23,234
	Income from Equity Investments			3,386		-		3,386		-			-			3,386
	Income (Loss) Before Income Taxes			20,058		12,498		32,556		65,472			(16,013	)		82,015
	Income Taxes			6,102		3,852		9,954		26,417			(9,821	)		26,550
	Net Income (Loss)			13,956		8,646		22,602		39,055			(6,192	)		55,465
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-		-		-		13			-			13
	Net Income (Loss) attributable to UIL Holdings		$	13,956	$	8,646	$	22,602	$	39,042		$	(6,192	)	$	55,452
	Total Capital Expenditures (1)		$	-	$	-	$	33,787	$	19,859		$	11,046		$	64,692
	(In Thousands)
			Three months ended March 31, 2013
			Electric Distribution and Transmission						Gas Distribution
			Distribution		Transmission		Total					Other			Total
	Operating Revenues		$	141,506	$	56,208	$	197,714	$	350,291		$	34		$	548,039
	Purchased power and gas			38,489		-		38,489		219,267			-			257,756
	Operation and maintenance			45,099		10,958		56,057		34,525			(1,323	)		89,259
	Transmission wholesale			-		18,818		18,818		-			-			18,818
	Depreciation and amortization			22,396		3,927		26,323		22,789			995			50,107
	Taxes - other than income taxes			12,139		7,311		19,450		16,196			220			35,866
	Operating Income			23,383		15,194		38,577		57,514			142			96,233
	Other Income and (Deductions), net			4,089		1,415		5,504		(857	)		714			5,361
	Interest Charges, net			6,940		3,128		10,068		7,196			6,048			23,312
	Income from Equity Investments			3,812		-		3,812		-			-			3,812
	Income (Loss) Before Income Taxes			24,344		13,481		37,825		49,461			(5,192	)		82,094
	Income Taxes			9,898		4,782		14,680		17,984			(2,377	)		30,287
	Net Income (Loss)			14,446		8,699		23,145		31,477			(2,815	)		51,807
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-		-		-		16			-			16
	Net Income (Loss) attributable to UIL Holdings		$	14,446	$	8,699	$	23,145	$	31,461		$	(2,815	)	$	51,791
	Total Capital Expenditures (1)		$	-	$	-	$	47,356	$	17,064		$	10,217		$	74,637
Reconciliation of Total Assets from Segments to Consolidated Financial Statements	'
	Electric Distribution and Transmission (2)
			Distribution		Transmission		Total					Other			Total (3)
										Gas Distribution (3)
	Total Assets at March 31, 2014		$	-	$	-	$	2,917,546	$	2,138,608		$	74,090		$	5,130,244
	Total Assets at December 31, 2013		$	-	$	-	$	2,950,707	$	2,010,246		$	183,267		$	5,144,220
	-1	Information for segmenting total capital expenditures between Distribution and Transmission is not available.  Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
	-2	Information for segmenting total assets between Distribution and Transmission is not available.  Total Electric Distribution and Transmission assets are disclosed in the Total Electric and Distribution and Transmission column.  Net plant in service is segregated by segment and, as of March 31, 2014, was $1,202.6 million and $660.7 million for Distribution and Transmission, respectively.  As of December 31, 2013, net plant in service was $1,181.1 million and $656.0 million for Distribution and Transmission, respectively.
	-3	Includes $266.2 million of goodwill in the Gas Distribution segment as of March 31, 2014 and December 31, 2013.

BUSINESS_ORGANIZATION_AND_STAT3

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES (Details) (USD $)	3 Months Ended				3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 02, 2014	Mar. 31, 2014	Mar. 31, 2014
			Philadelphia Gas Works [Member]	Philadelphia Gas Works [Member]	Philadelphia Gas Works [Member]	Philadelphia Gas Works [Member]
					Bridge Facility [Member]	Operating Expense [Member]
Ownership percentage in GenConn [Abstract]	'	'	'	'	'	'
Ownership percentage in joint venture (in hundredths)	50.00%	'	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'	'	'
Initial purchase price	'	'	'	$1,860,000,000	'	'
Acquisition related expenses	$5,051,000	$0	$11,500,000	'	$6,400,000	$5,100,000

BUSINESS_ORGANIZATION_AND_STAT4

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES, DERIVATIVES, EARNINGS PER SHARE (Details) (USD $)

3 Months Ended

Share data in Thousands, except Per Share data, unless otherwise specified

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Sep. 30, 2013

Mar. 31, 2014

Oct. 31, 2013

Contract

Current Assets [Member]

Current Assets [Member]

Deferred Charges and Other Assets [Member]

Deferred Charges and Other Assets [Member]

Current Liabilities [Member]

Current Liabilities [Member]

Noncurrent Liabilities [Member]

Noncurrent Liabilities [Member]

Weather Insurance Contracts [Member]

Weather Insurance Contracts [Member]

Weather Insurance Contracts [Member]

Weather Insurance Contracts [Member]

CapacityResource

Southern Connecticut Gas Company (SCG) [Member]

Southern Connecticut Gas Company (SCG) [Member]

Berkshire [Member]

Berkshire [Member]

Derivative [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gross derivative asset

$39,900,000

'

$9,073,000

$9,098,000

$30,868,000

$44,349,000

'

'

'

'

'

'

'

'

Regulatory asset

71,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Gross derivative liability

108,100,000

'

'

'

'

'

28,519,000

26,976,000

81,374,000

169,327,000

'

'

'

'

Gross derivative asset, UIL's portion of entity

3,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Gross derivative liability, UIL's portion of entity

62,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Regulatory liabilities

2,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum receivable amount allowed under weather insurance contract

'

'

'

'

'

'

'

'

'

'

'

3,000,000

'

1,000,000

Maximum payable amount allowed under weather insurance contract

'

'

'

'

'

'

'

'

'

'

'

2,000,000

'

200,000

Intrinsic value of contract

'

'

'

'

'

'

'

'

'

'

1,500,000

'

200,000

'

Derivatives [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of new capacity resources selected

4

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of Contracts for Differences (CfDs) approved by Public Utility Regulatory Authority (PURA)

4

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of Contracts for Differences (CfDs) executed by UI

2

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of Contracts for Differences (CfDs) executed by CL&P

2

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of cost borne by UI customers for CFDs (in hundredths)

20.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of cost borne by CL&P customers (in hundredths)

80.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrealized gain and losses from mark-to-market adjustments [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Regulatory Assets - Derivative liability

-71,619,000

-8,165,000

'

'

'

'

'

'

'

'

'

'

'

'

Regulatory Liabilities - Derivative assets

-2,942,000

0

'

'

'

'

'

'

'

'

'

'

'

'

Numerator [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income attributable to UIL Holdings

55,452,000

51,791,000

'

'

'

'

'

'

'

'

'

'

'

'

Less: Net income allocated to unvested units

30,000

71,000

'

'

'

'

'

'

'

'

'

'

'

'

Net income attributable to common shareholders

$55,422,000

$51,720,000

'

'

'

'

'

'

'

'

'

'

'

'

Denominator [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic average number of shares outstanding (in shares)

56,779

50,888

'

'

'

'

'

'

'

'

'

'

'

'

Effect of dilutive securities (in shares)

264

[1]

269

[1]

'

'

'

'

'

'

'

'

'

'

'

'

Diluted average number of shares outstanding (in shares)

57,043

51,157

'

'

'

'

'

'

'

'

'

'

'

'

Earnings per share [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic (in dollars per share)

$0.98

$1.02

'

'

'

'

'

'

'

'

'

'

'

'

Diluted (in dollars per share)

$0.97

$1.01

'

'

'

'

'

'

'

'

'

'

'

'

[1]

Includes unvested restricted stock and performance shares.

BUSINESS_ORGANIZATION_AND_STAT5

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES, EQUITY INVESTMENTS (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	Plant
Equity Investments [Abstract]	'	'	'
Income (loss) from equity investment	$3,386,000	$3,812,000	'
GenConn [Member]	'	'	'
Equity Investments [Abstract]	'	'	'
Number of peaking generation plants	2	'	'
Carrying value of joint venture	116,200,000	'	118,200,000
Undistributed earnings in equity method investment	200,000	'	'
Income (loss) from equity investment	3,400,000	3,800,000	'
Distributions received from joint venture	$5,400,000	$0	'

BUSINESS_ORGANIZATION_AND_STAT6

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES, REGULATORY ASSETS (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	$964,046,000		$1,036,130,000
Less current portion of regulatory assets	326,262,000		332,391,000
Regulatory Assets, Net	637,784,000		703,739,000
Assets decoupling amount	6,600,000		'
Nuclear Plant Investments - Above Market [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	238,868,000	[1]	238,868,000	[1]
Unamortized Redemption Costs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	11,101,000		11,301,000
Remaining period, minimum	'7 years		'
Remaining period, maximum	'19 years		'
Pension and Other Post-Retirement Benefit Plans [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	318,204,000	[2]	316,076,000	[2]
Environmental Remediation Costs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	15,444,000		14,953,000
Remaining period	'3 years		'
Hardship Programs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	21,696,000	[3]	25,019,000	[3]
Debt Premium [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	32,809,000		34,178,000
Remaining period, minimum	'1 year		'
Remaining period, maximum	'24 years		'
Deferred Purchased Gas [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	0	[4]	2,556,000	[4]
Income Taxes Due Principally to Book Tax Differences Assets [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	151,190,000	[5]	149,015,000	[5]
Deferred Income Taxes [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	41,935,000	[6]	32,517,000	[6]
Contracts For Differences [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	71,116,000	[7]	142,743,000	[7]
Term of contract minimum	'6 years		'
Term of contact maximum	'13 years		'
Excess Generation Service Charge [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	11,542,000	[8]	6,909,000	[8]
Deferred Transmission Income/Expense [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	8,719,000	[9]	9,615,000	[9]
Storm Costs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	14,573,000	[10]	14,752,000	[10]
Other [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	$26,849,000	[11]	$37,628,000	[11]
[1]	Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UIbs 2013 distribution rate request, PURA approved UIbs proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet.
[2]	Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) bPension and Other Benefitsb for additional information.
[3]	Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
[4]	Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
[5]	Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA.B Due to the end of the CTA charge, the CTA regulatory liabilities are classified as current regulatory liabilities and the regulatory assets not related to the CTA are reclassified as long-term regulatory assets.
[6]	The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
[7]	Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability. See b-Contracts for Differencesb discussion above for additional information.
[8]	Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
[9]	Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
[10]	Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) bRegulatory Proceedings b Electric Distribution and Transmission b Ratesb for a discussion of the recovery of these costs.
[11]	Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($6.6 million) and certain other amounts that are not currently earning a return. See Note (C) bRegulatory Proceedings for a discussion of the decoupling recovery period.

BUSINESS_ORGANIZATION_AND_STAT7

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES, REGULATORY LIABILITIES (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	$732,647		$706,821
Less current portion of regulatory liabilities	266,892		261,729
Regulatory Liabilities, Net	465,755		445,092
Accumulated Deferred Investment Tax Credits [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	4,428		4,465
Remaining period	'29 years		'
Income Taxes Due Principally to Book-Tax Differences [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	200,674	[1]	200,673	[1]
Deferred Gain on Sale of Property [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	37,933	[2]	37,933	[2]
Middletown/Norwalk Local Transmission Network Service Collections [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	21,258		21,402
Remaining period	'35 years		'
Pension and Other Post-Retirement Benefit Plans [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	26,094		27,686
Remaining period	'6 years		'
Deferred Income Taxes [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	24,276	[3]	43,421	[3]
Asset Retirement Obligation [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	6,793	[4]	5,593	[4]
Deferred Purchased Gas [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	3,537	[5]	0	[5]
Low Income Programs [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	28,488	[6]	25,300	[6]
Asset Removal Costs [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	325,375	[7]	319,530	[7]
Contracts For Differences [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	2,942	[8]	0	[8]
Non-Firm Margin Sharing Credits [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	24,667		0
Remaining period	'10 years		'
Other [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	$26,182	[7]	$20,818	[7]
[1]	Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA.B Due to the end of the CTA charge, the CTA regulatory liabilities are classified as current regulatory liabilities and the regulatory assets not related to the CTA are reclassified as long-term regulatory assets.
[2]	Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UIbs 2013 distribution rate request, PURA approved UIbs proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet.
[3]	The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
[4]	The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
[5]	Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
[6]	Various hardship and payment plan programs approved for recovery.
[7]	Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($6.6 million) and certain other amounts that are not currently earning a return. See Note (C) bRegulatory Proceedings for a discussion of the decoupling recovery period.
[8]	Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability. See b-Contracts for Differencesb discussion above for additional information.

BUSINESS_ORGANIZATION_AND_STAT8

BUSINESS ORGANIZATION AND STATEMENT OF ACCOUNTING POLICIES, STOCK BASED COMPENSATION (Details) (USD $)	3 Months Ended		1 Months Ended		3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
			Management [Member]	President and Chief Executive Officer [Member]	President and Chief Executive Officer [Member]
			Performance Shares [Member]	Restricted Stock [Member]	Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Number of shares granted (in shares)	'	'	123,940	2,196	'
Weighted average grant date fair value (in dollars per share)	'	'	$35.87	$35.87	'
Vesting period	'	'	'	'	'5 years
Vesting rights	'	'	'	'	'equal annual installments over a five year period
Total stock-based compensation expense	$2.50	$2.30	'	'	'

CAPITALIZATION_Details

CAPITALIZATION (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	14-May-14	Mar. 31, 2014
	CNG, 8.00% Noncallable [Member]	CNG, 8.00% Noncallable [Member]	Common Stock [Member]
		Subsequent Event [Member]
Temporary Equity [Line Items]	'	'	'
Common stock outstanding (in shares)	'	'	56,532,748
Common stock par value (in dollars per share)	'	'	$0
Preferred Stock of Subsidiaries, Noncontrolling Interests [Abstract]	'	'	'
Dividend rate of preferred stock (in hundredths)	8.00%	'	'
Par value per share (in dollars per share)	$3.13	'	'
Shares issued and outstanding (in shares)	108,706	'	'
Value of shares issued and outstanding	$0.30	'	'
Stock authorized but unissued (in shares)	775,609	'	'
Offering price in purchase of preferred shares (in dollars per share)	$7.50	$10.25	'

REGULATORY_PROCEEDINGS_Details

REGULATORY PROCEEDINGS (Details) (USD $)

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Feb. 15, 2013

Dec. 16, 2013

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Mar. 31, 2013

31-May-14

Aug. 14, 2013

Feb. 28, 2013

Sep. 30, 2012

Mar. 31, 2014

Mar. 31, 2014

Jan. 22, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

United Illuminating Company (UI) [Member]

Connecticut Natural Gas Corporation (CNG) [Member]

Connecticut Natural Gas Corporation (CNG) [Member]

Connecticut Natural Gas Corporation (CNG) [Member]

Connecticut Natural Gas Corporation (CNG) [Member]

The Southern Connecticut Gas Company (SCG) [Member]

The Berkshire Gas Company [Member]

GenConn Devon [Member]

GenConn Middletown [Member]

Bidder

Minimum [Member]

Maximum [Member]

Mechanism

Minimum [Member]

Maximum [Member]

Contract

Plant

Project

Megawatt

Rates [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Length of time for proposed rate amendment

'2 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Schedule of Regulatory Proceedings [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Allowed distribution return on equity (in hundredths)

'

'

'

'

'

'

'

8.75%

'

'

'

'

'

'

'

'

'

'

'

'

Allowed distribution return on equity per 2013 final decision (in hundredths)

'

'

'

'

'

'

'

9.15%

'

'

'

'

'

'

'

'

'

'

'

'

Earnings share split of profit

'

'

'

'

'

'

'

'50/50

'

'

'

'

'

'

'

'

'

'

'

'

Disallowance of deferred storm costs and capital costs per PURA final decision rate case

'

'

'

'

'

'

'

$22

'

'

'

'

'

'

'

'

'

'

'

'

Write-off related to disallowance of deferred storm costs and capital costs per PURA final decision in rate case, net of tax

'

'

'

'

17.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restoration of disallowed deferred storm costs per PURA final decision rate case

'

6.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restoration of disallowed capital costs per PURA final decision rate case

'

2.7

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Reversal of write-off related to deferred storm costs and capital costs per PURA final reconsideration decision

'

'

'

9.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Allowed recovery of storm costs, per PURA final decision rate case

'

45

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Regulatory asset related to storm recovery

'

'

14.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Power Supply Arrangements [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of standard service customers with wholesale power supply agreements in place for the first half of 2014 (in hundredths)

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of standard service customers with wholesale power supply agreements in place for the second half of 2014 (in hundredths)

'

'

80.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Collateral required to be posted if the entity's credit rating declined two ratings to fall below investment grade

'

'

12

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

New Renewable Source Generation [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum amount of commitment to purchase Renewable Energy Credits (RECs) from new facilities behind distribution customer meters

'

'

200

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Period of commitment to purchase Renewable Energy Credits (RECs)

'

'

'21 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Solicitation period obligations will phase-in

'

'

'6 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum annual commitment level obligation after year six

'

'

13.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of megawatts of grid connected renewable energy allowed to be developed by UI (in MW)

'

'

10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basis point added to return on equity (in hundredths)

'

'

0.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of UIs distribution load for which UI may be directed to enter to contracts for energy and/or RECs (in hundredths)

'

'

4.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of winning bidders approved by PURA

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of UI's distribution load represented by quantity of energy and RECs to be purchased, pending PURA approval (in hundredths)

'

'

3.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of long term contracts to purchase RECs from existing biomass facilities

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Transmission [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average return on equity (in hundredths)

'

'

'

'

'

'

'

'

'

'

12.10%

12.30%

'

'

'

'

'

'

'

'

Current approved base return on equity (in hundredths)

'

'

11.14%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Return on equity sought by complainants (in hundredths)

'

'

9.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Change in weighted average return on equity in basis points (in hundredths)

'

'

0.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Change in annual net income

'

'

0.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Return on equity per initial decision for refund period of October 1, 2011 through December 31, 2012 (in hundredths)

'

'

10.60%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Return on equity, per initial decision, for the period after final opinion issued by FERC (in hundredths)

'

'

9.70%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Reserve recorded by UI for refund

'

'

2.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Refund period

'

'

'15 Months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revised return on equity sought by complainants (in hundredths)

'

'

8.70%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

New England East-West Solution [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of inter related transmission projects

'

'

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of inter-related transmission projects with portions sited in Connecticut

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum amount of entity's investment for ownership of specific transmission assets

'

'

60

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold percentage of CL&P's costs for the Connecticut portions of projects (in hundredths)

'

'

8.40%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected amount of investment

'

'

60

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cumulative amount of deposits

'

'

36.1

'

'

'

0.7

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount of transmission assets

'

'

24.6

'

'

'

'

'

18.4

6.2

'

'

'

'

'

'

'

'

'

'

Pre-tax income earned on each deposit in NEEWS project

'

'

0.3

'

'

0.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity Investment in Peaking Generation [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ratio of equity investment in peaking generation for joint venture

'

'

'50-50

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of peaking generation plants

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenue requirements for equity investment in peaking generation

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30.8

37.5

Rates [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Approved return on equity (in hundredths)

'

'

'

'

'

'

'

'

'

'

'

'

'

9.18%

'

'

9.36%

10.50%

'

'

Duration of approved rate plan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

Number of rate making mechanisms

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

Earnings share mechanism ratio

'

'

'

'

'

'

'

'

'

'

'

'

'50/50

'

'

'

'

'

'

'

Decrease in annual revenue requirements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2.50

$3.50

'

'

'

'

SHORTTERM_CREDIT_ARRANGEMENTS_

SHORT-TERM CREDIT ARRANGEMENTS (Details) (USD $)	3 Months Ended
	Mar. 31, 2014
UIL [Member]	'
Disclosure of short-term credit arrangements [Abstract]	'
Maximum debt restriction amount	$1,600,000,000
Debt instrument, consolidated debt to consolidated capital ratio	0.77
Number of days of loan term agreement	'364 days
Standby Letter of Credit Due June 2014 [Member]	'
Disclosure of short-term credit arrangements [Abstract]	'
Standby letter of credit outstanding	4,400,000
Standby Letter of Credit Due January 2015 [Member] | UIL [Member]	'
Disclosure of short-term credit arrangements [Abstract]	'
Expiration date	16-Jun-14
Revolving Credit Facility [Member] | UIL [Member]	'
Disclosure of short-term credit arrangements [Abstract]	'
Expiration date	30-Nov-16
Available credit under the Credit Facility	395,600,000
Amounts outstanding under the Credit Facility	0
Bridge Facility [Member] | UIL [Member]	'
Disclosure of short-term credit arrangements [Abstract]	'
Maximum borrowing capacity	1,900,000,000
Bridge Facility [Member] | WGP [Member]	'
Disclosure of short-term credit arrangements [Abstract]	'
Amounts outstanding under the Credit Facility	0
Borrowing limit	$950,000,000

INCOME_TAXES_Details

INCOME TAXES (Details)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
INCOME TAXES [Abstract]	'	'
Combined statutory federal and state income tax rates (in hundredths)	40.90%	40.90%
Effective book income tax rates (in hundredths)	33.40%	36.90%

SUPPLEMENTARY_INFORMATION_Deta

SUPPLEMENTARY INFORMATION (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Depreciation and Amortization	'	'
Property, plant and equipment depreciation	$31,988	$29,351
Amortization of regulatory assets	8,330	20,756
Total Depreciation and Amortization	40,318	50,107
Taxes - Other than Income Taxes	'	'
Connecticut gross earnings	22,714	21,964
Local real estate and personal property	11,964	10,713
Payroll taxes	3,857	2,793
Other	1,001	396
Total Taxes - Other than Income Taxes	39,536	35,866
Other Income and (Deductions)	'	'
Interest income	542	764
Allowance for funds used during construction - equity	2,550	2,537
Allowance for funds used during construction - debt	1,410	2,370
Weather insurance	-1,906	24
Other	1,266	-334
Total Other Income and (Deductions)	$3,862	$5,361

PENSION_AND_OTHER_BENEFITS_Det

PENSION AND OTHER BENEFITS (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plan Disclosure [Line Items]	'	'
Pension contributions	$7,700,000	'
Additional contribution during remainder of 2014	15,300,000	'
Pension Benefit [Member]	'	'
Components of net periodic benefit cost:	'	'
Service cost	2,896,000	3,696,000
Interest cost	11,019,000	9,988,000
Expected return on plan assets	-13,560,000	-12,863,000
Amortization of:	'	'
Prior service costs	73,000	151,000
Actuarial loss	3,097,000	5,208,000
Net periodic benefit cost	3,525,000	6,180,000
Pension Benefit [Member] | Minimum [Member]	'	'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'	'
Discount rate (in hundredths)	4.90%	4.00%
Average wage increase (in hundredths)	3.50%	3.50%
Return on plan assets (in hundredths)	7.75%	7.75%
Pension Benefit [Member] | Maximum [Member]	'	'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'	'
Discount rate (in hundredths)	5.20%	4.25%
Average wage increase (in hundredths)	3.80%	3.80%
Return on plan assets (in hundredths)	8.00%	8.00%
Other Postretirement Benefits [Member]	'	'
Components of net periodic benefit cost:	'	'
Service cost	404,000	481,000
Interest cost	1,487,000	1,384,000
Expected return on plan assets	-700,000	-648,000
Amortization of:	'	'
Prior service costs	71,000	-13,000
Actuarial loss	-172,000	444,000
Net periodic benefit cost	$1,090,000	$1,648,000
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'	'
Composite health care trend rate (current year) (in hundredths)	7.00%	7.50%
Composite health care trend rate (2018 forward) (in hundredths)	5.00%	5.00%
Other Postretirement Benefits [Member] | Minimum [Member]	'	'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'	'
Discount rate (in hundredths)	4.85%	4.00%
Return on plan assets (in hundredths)	5.56%	5.56%
Other Postretirement Benefits [Member] | Maximum [Member]	'	'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'	'
Discount rate (in hundredths)	5.20%	4.25%
Return on plan assets (in hundredths)	8.00%	8.00%

RELATED_PARTY_TRANSACTIONS_Det

RELATED PARTY TRANSACTIONS (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
RELATED PARTY TRANSACTIONS [Abstract]	'	'
Lease payments for office space	$0.50	$0.40

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
	Subcontractor
Connecticut Yankee Atomic Power Company [Member]	'
Site Contingency [Line Items]	'
Percentage stock ownership share in CT Yankee atomic power company (in hundredths)	9.50%
Carrying value of stock in CT Yankee atomic power company	$0.10
DOE spent fuel litigation [Abstract]	'
Damages awarded for spent fuel related costs	39.7
Entity's share of amount awarded to CT Yankee atomic power company	3.8
Actual second set of damages award	126.3
Entity's share of second set of damage claims	12
Mill River New Haven Connecticut Site [Member]	'
Site Decontamination, Demolition and Remediation Costs [Abstract]	'
Amount placed in escrow for estimated remediation	1.9
Remaining amount of escrow	0.1
New Haven Harbor Station Site [Member]	'
Site Decontamination, Demolition and Remediation Costs [Abstract]	'
Site contingency, liability accrued	3.2
Mill Street Greenfield Massachusetts Site [Member]	'
Site Decontamination, Demolition and Remediation Costs [Abstract]	'
Site contingency, liability accrued	2.9
East Street Site Pittsfield Massachusetts [Member]	'
Site Decontamination, Demolition and Remediation Costs [Abstract]	'
Site contingency, liability accrued	1.2
Middletown/Norwalk Transmission Projects [Member]	'
Middletown/Norwalk Transmission Project [Abstract]	'
Amount sought for change order requests	33.3
Percentage of general contractor mark-up on approved subcontractor change order claims (in hundredths)	10.00%
Amount of general contractor mark up on approved subcontractor change order claims	2.3
Subcontractors responsible for civil construction	2
Revised estimate for change order requests	7.7
Amount in Memorandum of Decision issued by the court for the company to pay to contractor	$1.30

FAIR_VALUE_MEASUREMENTS_Detail

FAIR VALUE MEASUREMENTS (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:	'	'
Derivative assets	$39,941	$53,447
Noncurrent investments available for sale	11,318	11,148
Deferred Compensation Plan	3,371	3,775
Supplemental retirement benefit trust life insurance policies	7,976	7,898
Total financial assets, fair value	62,606	76,268
Liabilities:	'	'
Derivative liabilities	108,166	196,233
Long-term debt	1,901,438	1,846,867
Total financial liabilities, fair value	2,009,604	2,043,100
Net fair value assets/(liabilities)	-1,946,998	-1,966,832
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Assets:	'	'
Derivative assets	0	0
Noncurrent investments available for sale	11,318	11,148
Deferred Compensation Plan	3,371	3,775
Supplemental retirement benefit trust life insurance policies	0	0
Total financial assets, fair value	14,689	14,923
Liabilities:	'	'
Derivative liabilities	0	0
Long-term debt	0	0
Total financial liabilities, fair value	0	0
Net fair value assets/(liabilities)	14,689	14,923
Significant Other Observable Inputs (Level 2) [Member]	'	'
Assets:	'	'
Derivative assets	0	0
Noncurrent investments available for sale	0	0
Deferred Compensation Plan	0	0
Supplemental retirement benefit trust life insurance policies	7,976	7,898
Total financial assets, fair value	7,976	7,898
Liabilities:	'	'
Derivative liabilities	0	0
Long-term debt	1,901,438	1,846,867
Total financial liabilities, fair value	1,901,438	1,846,867
Net fair value assets/(liabilities)	-1,893,462	-1,838,969
Significant Unobservable Inputs (Level 3) [Member]	'	'
Assets:	'	'
Derivative assets	39,941	53,447
Noncurrent investments available for sale	0	0
Deferred Compensation Plan	0	0
Supplemental retirement benefit trust life insurance policies	0	0
Total financial assets, fair value	39,941	53,447
Liabilities:	'	'
Derivative liabilities	108,166	196,233
Long-term debt	0	0
Total financial liabilities, fair value	108,166	196,233
Net fair value assets/(liabilities)	($68,225)	($142,786)

FAIR_VALUE_MEASUREMENTS_Unobse

FAIR VALUE MEASUREMENTS, Unobservable Input Reconciliation (Details) (Contract For Difference [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
Contract For Difference [Member]	'	'
Unobservable Input [Abstract]	'	'
Risk of non-performance, lower range (in hundredths)	0.00%	0.00%
Risk of non-performance, upper range (in hundredths)	0.69%	0.62%
Discount rate, lower range (in hundredths)	1.73%	1.75%
Discount rate, upper range (in hundredths)	2.88%	3.21%
Forward pricing, lower range (in dollars per MW)	$2.95	$1.40
Forward pricing, upper range (in dollars per MW)	$14.59	$9.83

FAIR_VALUE_MEASUREMENTS_Assets

FAIR VALUE MEASUREMENTS, Assets and Liabilities Classified as level 3 (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Changes in fair value of assets and liabilities classified as level 3 [Roll Forward]	'
Net fair value assets/(liabilities), Beginning balance	($142,786)
Unrealized gains and (losses), net [Abstract]	'
Included in earnings	0
Included in regulatory assets/(liabilities)	74,561
Settlements	0
Net fair value assets/(liabilities), Ending balance	-68,225
Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of March 31, 2014	$74,561

FAIR_VALUE_MEASUREMENTS_Regula

FAIR VALUE MEASUREMENTS, Regulatory Assets and Liabilities (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Change in regulatory asset/liability balances [Roll Forward]	'
Net regulatory assets/(liabilities), Beginning balance	$142,786
Unrealized (gains) and losses, net	-74,561
Net regulatory assets/(liabilities), Ending balance	$68,225

SEGMENT_INFORMATION_Details

SEGMENT INFORMATION (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Segment Reporting Information [Line Items]	'		'		'
Operating Revenues	$571,162,000		$548,039,000		'
Purchased power and gas	268,055,000		257,756,000		'
Operation and maintenance	92,877,000		89,259,000		'
Transmission wholesale	20,911,000		18,818,000		'
Depreciation and amortization	40,318,000		50,107,000		'
Taxes - other than income taxes	39,536,000		35,866,000		'
Acquisition-related expenses	5,051,000		0		'
Operating Income	104,414,000		96,233,000		'
Other Income and (Deductions), net	-2,551,000		5,361,000		'
Interest Charges, net	23,234,000		23,312,000		'
Income from Equity Investments	3,386,000		3,812,000		'
Income (Loss) Before Income Taxes	82,015,000		82,094,000		'
Income Taxes	26,550,000		30,287,000		'
Net Income (Loss)	55,465,000		51,807,000		'
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	13,000		16,000		'
Net Income (Loss) attributable to UIL Holdings	55,452,000		51,791,000		'
Total Capital Expenditure	64,692,000	[1]	74,637,000	[1]	'
Total Assets	5,130,244,000	[2]	'		5,144,220,000	[2]
Net plant in service segregated by segment [Abstract]	'		'		'
Goodwill	266,205,000		'		266,205,000
Electric Distribution Reportable Segment [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Operating Revenues	145,189,000		141,506,000		'
Purchased power and gas	53,130,000		38,489,000		'
Operation and maintenance	45,817,000		45,099,000		'
Transmission wholesale	0		0		'
Depreciation and amortization	12,063,000		22,396,000		'
Taxes - other than income taxes	12,861,000		12,139,000		'
Acquisition-related expenses	0		'		'
Operating Income	21,318,000		23,383,000		'
Other Income and (Deductions), net	3,186,000		4,089,000		'
Interest Charges, net	7,832,000		6,940,000		'
Income from Equity Investments	3,386,000		3,812,000		'
Income (Loss) Before Income Taxes	20,058,000		24,344,000		'
Income Taxes	6,102,000		9,898,000		'
Net Income (Loss)	13,956,000		14,446,000		'
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	0		0		'
Net Income (Loss) attributable to UIL Holdings	13,956,000		14,446,000		'
Total Capital Expenditure	0	[1]	0	[1]	'
Total Assets	0	[3]	'		0	[3]
Electric Transmission Reportable Segment [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Operating Revenues	58,788,000		56,208,000		'
Purchased power and gas	0		0		'
Operation and maintenance	10,581,000		10,958,000		'
Transmission wholesale	20,911,000		18,818,000		'
Depreciation and amortization	4,225,000		3,927,000		'
Taxes - other than income taxes	8,352,000		7,311,000		'
Acquisition-related expenses	0		'		'
Operating Income	14,719,000		15,194,000		'
Other Income and (Deductions), net	983,000		1,415,000		'
Interest Charges, net	3,204,000		3,128,000		'
Income from Equity Investments	0		0		'
Income (Loss) Before Income Taxes	12,498,000		13,481,000		'
Income Taxes	3,852,000		4,782,000		'
Net Income (Loss)	8,646,000		8,699,000		'
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	0		0		'
Net Income (Loss) attributable to UIL Holdings	8,646,000		8,699,000		'
Total Capital Expenditure	0	[1]	0	[1]	'
Total Assets	0	[3]	'		0	[3]
Total Electric Reportable Segments [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Operating Revenues	203,977,000		197,714,000		'
Purchased power and gas	53,130,000		38,489,000		'
Operation and maintenance	56,398,000		56,057,000		'
Transmission wholesale	20,911,000		18,818,000		'
Depreciation and amortization	16,288,000		26,323,000		'
Taxes - other than income taxes	21,213,000		19,450,000		'
Acquisition-related expenses	0		'		'
Operating Income	36,037,000		38,577,000		'
Other Income and (Deductions), net	4,169,000		5,504,000		'
Interest Charges, net	11,036,000		10,068,000		'
Income from Equity Investments	3,386,000		3,812,000		'
Income (Loss) Before Income Taxes	32,556,000		37,825,000		'
Income Taxes	9,954,000		14,680,000		'
Net Income (Loss)	22,602,000		23,145,000		'
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	0		0		'
Net Income (Loss) attributable to UIL Holdings	22,602,000		23,145,000		'
Total Capital Expenditure	33,787,000	[1]	47,356,000	[1]	'
Total Assets	2,917,546,000	[3]	'		2,950,707,000	[3]
Gas Distribution Reportable Segment [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Operating Revenues	367,185,000		350,291,000		'
Purchased power and gas	214,925,000		219,267,000		'
Operation and maintenance	39,656,000		34,525,000		'
Transmission wholesale	0		0		'
Depreciation and amortization	21,748,000		22,789,000		'
Taxes - other than income taxes	17,640,000		16,196,000		'
Acquisition-related expenses	0		'		'
Operating Income	73,216,000		57,514,000		'
Other Income and (Deductions), net	-981,000		-857,000		'
Interest Charges, net	6,763,000		7,196,000		'
Income from Equity Investments	0		0		'
Income (Loss) Before Income Taxes	65,472,000		49,461,000		'
Income Taxes	26,417,000		17,984,000		'
Net Income (Loss)	39,055,000		31,477,000		'
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	13,000		16,000		'
Net Income (Loss) attributable to UIL Holdings	39,042,000		31,461,000		'
Total Capital Expenditure	19,859,000	[1]	17,064,000	[1]	'
Total Assets	2,138,608,000	[2]	'		2,010,246,000	[2]
Net plant in service segregated by segment [Abstract]	'		'		'
Goodwill	266,200,000		'		266,200,000
Other [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Operating Revenues	0		34,000		'
Purchased power and gas	0		0		'
Operation and maintenance	-3,177,000		-1,323,000		'
Transmission wholesale	0		0		'
Depreciation and amortization	2,282,000		995,000		'
Taxes - other than income taxes	683,000		220,000		'
Acquisition-related expenses	5,051,000		'		'
Operating Income	-4,839,000		142,000		'
Other Income and (Deductions), net	-5,739,000		714,000		'
Interest Charges, net	5,435,000		6,048,000		'
Income from Equity Investments	0		0		'
Income (Loss) Before Income Taxes	-16,013,000		-5,192,000		'
Income Taxes	-9,821,000		-2,377,000		'
Net Income (Loss)	-6,192,000		-2,815,000		'
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	0		0		'
Net Income (Loss) attributable to UIL Holdings	-6,192,000		-2,815,000		'
Total Capital Expenditure	11,046,000	[1]	10,217,000	[1]	'
Total Assets	74,090,000		'		183,267,000
Distribution Segment [Member]	'		'		'
Net plant in service segregated by segment [Abstract]	'		'		'
Net plant in service	1,202,600,000		'		1,181,100,000
Transmission Segment [Member]	'		'		'
Net plant in service segregated by segment [Abstract]	'		'		'
Net plant in service	$660,700,000		'		$656,000,000
[1]	Information for segmenting total capital expenditures between Distribution and Transmission is not available. B Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
[2]	Includes $266.2 million of goodwill in the Gas Distribution segment as of March 31, 2014 and December 31, 2013.
[3]	Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric and Distribution and Transmission column. Net plant in service is segregated by segment and, as of March 31, 2014, was $1,202.6 million and $660.7 million for Distribution and Transmission, respectively. As of December 31, 2013, net plant in service was $1,181.1 million and $656.0 million for Distribution and Transmission, respectively.